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SOLVED -- It's back..... again.

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    Posted: March-22-2019 at 11:33pm
Got the boat out today to get it ready for the season since the temps in my parts are now consistently well above freezing at night and into the 60's for the day.   Topped off the batteries and got them installed, checked all the fluids, hooked up the water and turned her over.   She fired right up with no issues or problems.   Until ....

After the initial 4 or 5 second "warm-up' phase at a higher idle it dropped back down and as normal, started a bit of a rolling idle ... some call it surging, as I originally did. I'd always had this issue since the day I bought the boat and had tried nearly everything to get rid of it, mostly to no avail.   Then after the new engine break-in and a new distributor last fall it seemed the issue had finally, for the most part, been checked. After a cold start and initial few second high idle it would settle back down and roll between 700 and 1000 rpm's but only for about 5 seconds or less ( only about 2 seconds if it was already warm).. Then it would level off and be rock solid, well pretty much indefinitely.   Good. Finally handled.    Until first start this year. I kept waiting for it to taper off, then settle to an even idle, but it never did. Again, I tried everything to see what may be an issue this time, but heck, nearly everything is new!   Well, the electronic parts anyway.   I have not replaced the TFI, throttle body or coil but not sure any of those has ever been linked to this issue and all seem to functioning well.   I've checked for vac leaks and can't seem to locate any.

So, the question here is obvious - what am I missing??    

Thanks and at this point, any thoughts or even crazy ideas would be welcome.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gary S Quote  Post ReplyReply Direct Link To This Post Posted: March-23-2019 at 12:10am
There was a reason the ECM tune went from the “290” to the “300” in the later engines thought it was for rolling idle issues. Didn’t you get the programmer for the moats chips? Did you get a Mustang ECM? Might be worth trying if you have everything.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gt40KS Quote  Post ReplyReply Direct Link To This Post Posted: March-23-2019 at 1:55am
Have it, done it Gary.   It is installed already and yes, with the 300 tune.   But thanks for the thought.
I don't remember if I had ever ran the engine for very long after the install though.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: March-23-2019 at 5:40am
I'm pretty sure you have done this but if not take a can of carb cleaner with the 6" spray tube on it. Clean the Throttle body butterfly and the housing it operates in. There may be a couple very small air bleeds in the throttle body, usually the tube on the carb cleaner can slip into those small tubes allowing you to blast them clean.
With a clean rag spray some carb cleaner on the rag and wipe the throttle body butterfly and the area it seats when closed.   Crank the throttle all the way open and clean as much of the butterfly and internal throttle body as you can. A clean rag wipe will leave visible dirt on the rag after the wipe if there was any to be removed. I have seen build up of crud inside the throttle body cause the butterfly not operate at idle as it should, or get sticky just enough to give you fits at idle. I have seen it in cars and they have good paper air filters.
Our boats only have a mesh screen so I would think the build up would be worse in a boat.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: March-23-2019 at 8:51am
Did you ever take Carnac's suggestion ,and remember the color choice is yours
Originally posted by gt40KS gt40KS wrote:

Originally posted by KENO KENO wrote:

Hi Joe

I checked with this guy

and he said he didn't have a clue but that as a guess, an adjustable fuel pressure regulator and gauge might come in handy for some adjustment of your fuel pressure/flow to see if that helps in case it's an issue with the ECM not being able to compensate..

You can probably find one to match your color scheme too. Red, white, blue, black silver or even yellow to match the hull intake


BINGO !!    Found just the right thing ... all the correct colors anyway   
Thanks for the suggestion



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Post Options Post Options   Thanks (0) Thanks(0)   Quote gt40KS Quote  Post ReplyReply Direct Link To This Post Posted: March-23-2019 at 1:33pm
Both good suggestions, thanks. Mark, while rebuilding last winter/ spring I did clean the throttle body fairly well, though I didn't go all out with the carb cleaner as you suggested. It's certainly worth a try.
Ken, after your suggestions last summer I did get a fuel pressure gauge on the system to verify everything was in spec, which it was and didn't seem like there were any fluctuations with the pressure on the line.   I guess I'm not understanding what I'd be doing with the new FPR if the current stock one is keeping everything within spec.   Could you enlighten me?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: March-23-2019 at 1:48pm
Originally posted by gt40KS gt40KS wrote:

Both good suggestions, thanks. Mark, while rebuilding last winter/ spring I did clean the throttle body fairly well, though I didn't go all out with the carb cleaner as you suggested. It's certainly worth a try.
Ken, after your suggestions last summer I did get a fuel pressure gauge on the system to verify everything was in spec, which it was and didn't seem like there were any fluctuations with the pressure on the line.   I guess I'm not understanding what I'd be doing with the new FPR if the current stock one is keeping everything within spec.   Could you enlighten me?


If your ECM is running things a little lean at idle as programmed and you have an adjustable regulator, you can richen the mixture everywhere with a small pressure increase.

You can search on CCF for "crushing the regulator" or something along those lines as a cure for the idle issues for at least one person.





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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: March-23-2019 at 1:51pm
Or just read this link

link
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gt40KS Quote  Post ReplyReply Direct Link To This Post Posted: March-23-2019 at 2:38pm
Ok, got it Ken. Long read to get to the nitty gritty but all well worth it as I've done virtually everything mentioned, except actually trying to increase rail pressure a bit.   Funny, I remember reading something about this before and like "Bo" I had mainly dismissed it because the rail pressure never seemed to drop below spec.   This too is now on the list of worth a try.   Thanks!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: March-23-2019 at 3:27pm
Your engine has a pressure regulator on the fuel rail that will limit your max fuel pressure.
Has it been changed?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gt40KS Quote  Post ReplyReply Direct Link To This Post Posted: March-23-2019 at 6:24pm
No Mark, original unit as far as I know. It does however at least seem to function properly.   PO had said he was told the "top end" of the engine (presumably intake and above) was original to the boat. And based on the condition of the rest of it when I bought it, very little had ever been done to maintain it over the years so I highly doubt it had ever been replaced.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gt40KS Quote  Post ReplyReply Direct Link To This Post Posted: March-24-2019 at 12:56pm
I'm curious if anyone has ever swapped their stock FPR with and aftermarket adjustable, and if so, how did they attach it to the fuel rail. Looking at it again, the stock one mounts to the rail on a 3 point flange and with a ton of google-fu yesterday I could not find a single unit with a compatible mount. I figured with the limited space between the rail and the ECC I'd have to remote mount the new one and run new lines to the rail and return. But how to connect the new fuel line to the rail, in place of the stock FPR has me perplexed - I don't really want a comically-engineered concoction. I'm also NOT looking for the "cheapest" regulator out there. Most, if not all of those are indeed cheap, Chinese made junk that likely will fail or malfunction fairly quickly.   
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: March-24-2019 at 7:16pm
I tried some of your Google Fu and came up with one of these

link

It's not Chinese, it's not junk and it's expensive but it mounts just like the original.

Maybe it takes up no more space than the original, a phone call might be helpful.

If was out backyard hacking a solution, I might pull the vacuum line from the original regulator , which should make it put out about 40 psi at idle instead of 31 or so and see if that makes it idle smoothly with a richer mix due to the extra pressure.

With the vacuum line off and plugged, it'll put out the same pressure all the time which wouldn't be too good for fuel economy/optimum fuel/air ratio.

If it smoothed things out, then an adjustable regulator would be handy to fine tune things.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gt40KS Quote  Post ReplyReply Direct Link To This Post Posted: March-24-2019 at 11:48pm
Perfect! Somehow I was thinking you'd be able to come up with the exact thing I needed    Think I will try removing the vac hose tomorrow though. Thanks again, Ken
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gt40KS Quote  Post ReplyReply Direct Link To This Post Posted: April-27-2019 at 11:16pm
Finally had time today to install the new adjustable pressure regulator that Ken - in his seemingly infinite wisdom - pointed me to. Install was tight quarters and in the end I'll have to leave the ECM bracket loose at the top so I don't arc on the back of the 50 amp breaker, but all went well.   Started the engine and my original guess at the setting was only a few PSI off where she purrs like a kitten!   At idle this new engine requires a few more PSI than that of a stock GT-40 to eliminate those pesky rolling idle issues. - 46 instead of the 39 +/- stock value       I've renamed the title as solved, but I do need to do a lake test to really confirm.





Ken, I'd say don't let your head get too big on this one but I fear it's probably too late
Thanks a bunch to everyone for all the help and suggestions on this very frustrating problem     

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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: April-27-2019 at 11:39pm
Joe, Joe Joe

Never count your chickens till they're hatched and never call it cured till that test run

That Carnac, he's OK

Uncharacteristically, I like your color choice

Hope it runs like you're expecting it to.

PS The head never gets big, cause there's always something coming along to make you feel like you really don't know much.

PS Idle numbers should be around 31 and full throttle numbers around 39 before adjustment are done.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gt40KS Quote  Post ReplyReply Direct Link To This Post Posted: June-16-2019 at 11:52pm
Alright Ken .... FINALLY had the opportunity to get to the lake for that test run. Everything ran great without any rolling idle issues all day. Seems like this chapter can indeed be closed. Thanks again   
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jonny Quest Quote  Post ReplyReply Direct Link To This Post Posted: June-17-2019 at 2:55am
Way to go TEAM RED. Like KENO, I also approve of the color choice.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: June-17-2019 at 3:30am
Nice work Men! Now Joe, do we get some numbers on how that beast is powering you on the water or do we have to imagine how fast it is. I know you did a lot of work getting it into first class shape. I hope it is finally giving back for you.
Happy Fathers day.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: June-17-2019 at 7:21am
Originally posted by gt40KS gt40KS wrote:

Alright Ken .... FINALLY had the opportunity to get to the lake for that test run. Everything ran great without any rolling idle issues all day. Seems like this chapter can indeed be closed. Thanks again   


Glad it's running good Joe

Hopefully it's good at all RPMs and not a real gas guzzler with the extra fuel pressure
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gt40KS Quote  Post ReplyReply Direct Link To This Post Posted: June-17-2019 at 10:41pm
No numbers this time out - didn't think about it at the time. But the day was cut short of what I would have liked due to gusty winds that came up only an hour or so after I had gotten out on the water. Didn't realize it at first since I was hanging out close to the dam where it's usually pretty calm anyway. Sure made the drive back to the dock interesting though.

Too early in the 'testing' phase to ascertain about the MPG Ken but I can say that while I still haven't taken her to full throttle she jumps out of the hole so hard and fast at 3/4 I'm thinking it would hank a guys arms right out of their sockets!   But from what I observed the standard 1 to 1 rule seems to be holding very true up to about 45mph. I am curious, and a bit concerned perhaps just how much throttle is left at that point. The engine was still climbing and pulling hard when I pulled it back to visually register the 45@45 (rpm@mph) indicating the probability that If I had gone to WOT the top may have been well above 5000.   But, we won't know that for a while yet. The engine is still fresh and although I've been assured by many very respected members here that at this point I could "drive it like I stole it", I've decided 2/3 to 3/4 is quite enough for now since I've still got the vacation @ Beaver Lake (Arkansas) with the whole family coming up in mid July. (my boat is kinda the main attraction).    

After we get back, well that's probably a different story      And maybe then I'll have more to report about MPG's & such.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: June-18-2019 at 5:48am
Sounds like you have it dialed in now Joe. Get some hours on it and enjoy.
I have had 6 props on my GT40 in the last 5 years, well, one of these was rebuilt twice but I count that prop as 3 since it was different afer each repair.
I have seen 5,300 RPM.   My new Acme 422 seems to top out right around 5,000 RPM but I only ran that prop a few times last year so I am trying to remember exact RPM with this prop. I think you run the same prop. ( along with the same great color scheme!)

As far as break-in rules on a new engine. #1, #2 and #3 are the same.
Don't overheat it.
Other than that after twenty minutes run time everything is ready to run.
Don't leave it at wide open for any period of time when new but to open it up and run from idle to top speed and then back off to cool is fine.
Nascar builds engines and then go out and run wide open for 4 hours.
Drag racers build new engines and drag race them right away.
Off shore boat engines are installed brand new and race the next weekend.
IF they are assembled correctly they stay together. If not they break.
If something is wrong it will break right away when pushed, same will happen even if you give it a long break in.
New engines will run hotter than old engines, there is more friction and good compression.
For this reason pay close attention to temperature, far more important than what RPM you run.
A new engine at wide open throttle will build more heat faster, for this reason back off after a quick hard run to let the parts cool After 2 hours use and an oil change I would eliminate all restrictions.
Go have fun.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: June-18-2019 at 8:34am
Originally posted by KENO KENO wrote:

Originally posted by gt40KS gt40KS wrote:

Alright Ken .... FINALLY had the opportunity to get to the lake for that test run. Everything ran great without any rolling idle issues all day. Seems like this chapter can indeed be closed. Thanks again   


Glad it's running good Joe

Hopefully it's good at all RPMs and not a real gas guzzler with the extra fuel pressure


I wasn't so much concerned with gas mileage as with how it runs through the rest of the RPM range and it sounds like it's doing plenty good.

I'll let Carnac know that things worked out well

Maybe all those people with rolling idle issues should take Carnac's suggestion and get an adjustable regulator.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: July-09-2019 at 6:32am
Ken I have been told by a few including my son that it is not wise to modify the camshaft with one of these early Ford FI systems. My son does a lot a tuning on High Horsepower cars, 500-1000 HP turbo engines mostly but he dables in many automotive issues including one buddy that installed an early 90's Ford FI system on a 67 Mustang, made that work well and then twin turbo charged it to 650 HP and then made that work well.
How well, how about a 650 HP mustang with a non overdrive tranny getting 23 MPG at 70 on the highway while offering 650 HP and 12 second quarter mile times while fighting traction all the way down the track. He still has tuning work to do to race it.

Anyhow my son says if you give the Ford system more camshaft it is not able to compensate to give us reliable engine management for easy boat use.

I am wondering if your simple increase of fuel pressure works around some of these shortcomings and gives us more options.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote man0seven Quote  Post ReplyReply Direct Link To This Post Posted: July-09-2019 at 12:06pm
Joe,
Was your rolling idle issue constant? After it comes off its original high idle does it stay rolling indefinitely?
I have been struggling with mine and it is constantly rolling besides the first spurt.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote halfnelly Quote  Post ReplyReply Direct Link To This Post Posted: July-09-2019 at 12:43pm
Originally posted by MrMcD MrMcD wrote:

Ken I have been told by a few including my son that it is not wise to modify the camshaft with one of these early Ford FI systems. My son does a lot a tuning on High Horsepower cars, 500-1000 HP turbo engines mostly but he dables in many automotive issues including one buddy that installed an early 90's Ford FI system on a 67 Mustang, made that work well and then twin turbo charged it to 650 HP and then made that work well.
How well, how about a 650 HP mustang with a non overdrive tranny getting 23 MPH at 70 on the highway while offering 650 HP and 12 second quarter mile times while fighting traction all the way down the track. He still has tuning work to do to race it.

Anyhow my son says if you give the Ford system more camshaft it is not able to compensate to give us reliable engine management for easy boat use.

I am wondering if your simple increase of fuel pressure works around some of these shortcomings and gives us more options.


The earlier (86-88) EEC-IV Mustang FI systems were a speed density system, they do not tolerate camshafts, boost, etc because the ECM would need to be reprogrammed. The 89+ models were a mass air setup which can learn and compensate for camshafts, supercharging, turbocharging, etc. Seeing that the marine version is also a speed density setup, there's probably not much you can do with the stock ECM as far as cams go. Perhaps someone wants to guinea pig swapping an 89+ ECM and mass air meter into their Nautique? Then the sky is the limit.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: July-09-2019 at 3:03pm
Thanks
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Post Options Post Options   Thanks (1) Thanks(1)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: July-09-2019 at 3:46pm
Originally posted by man0seven man0seven wrote:

Joe,
Was your rolling idle issue constant? After it comes off its original high idle does it stay rolling indefinitely?
I have been struggling with mine and it is constantly rolling besides the first spurt.


Joe will probably tell you it was pretty much constant.

His was a rebuilt engine with GT40p heads, a slightly hotter camshaft maybe .030 over and at least as many new parts as you've listed and that lope came with it at no extra cost.

The adjustable regulator seems to have made him happy.

In the past some people had cured their lope by "crushing" the regulator to raise pressure so an adjustable seemed a little more precise

I think it's pretty hard to "uncrush" a regulator once it's been done

He'll be along sometime to comment
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gt40KS Quote  Post ReplyReply Direct Link To This Post Posted: July-10-2019 at 1:59am
Originally posted by man0seven man0seven wrote:

Joe,
Was your rolling idle issue constant? After it comes off its original high idle does it stay rolling indefinitely?
I have been struggling with mine and it is constantly rolling besides the first spurt.


I know your pain Brian!   Mine ended up being a bit more complex because I bought the boat with the legacy problem and fought with it for quite a while that first fall. At some point I ended up replacing the entire engine (long story) with a sort of hybrid - i.e. all the GT40 electronics and fuel from the old engine but a modified verson for the long block.   At first it seemed the rolling idle had disipated (not gone though) but it wasn't long before it was back with a vengence.   Like you I had already replaced almost everything but to no avail. Then I read something in a Mustang forum about the same issue that stated there had been no less than 7 identified possible causes of this issue, any one of which could cause the problem, but many were finding out that it was not one but a few of these combined.
Going down through their list I discovered something I hadn't read before - the PIP sensor in the distributor can wear out or become loose causing the timing to fluctuate and ultimately the RPM. So I bought a good automotive version from Rock and after installation the engine was now back to where I had it right after the build. Ok, one down, but obviously there's got to be something else.   That's when I posted this thread and where Ken suggested the use of the adjustable regulator. The reasoning here was like one of those big, bright light bulbs going off in your face - the proverbial 'duh' moment. My modified engine likely isn't going to follow the same pressue requirements of the stock GT40's.   So in goes the new regulator, pumped up 6 or so psi over stock and bam - rolling idle gone!!    Yep, Ken can be pretty handy to have on this here forum
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Post Options Post Options   Thanks (0) Thanks(0)   Quote man0seven Quote  Post ReplyReply Direct Link To This Post Posted: July-15-2019 at 1:57pm
Hi Joe,
The regulator didn't solve my issue. I ran it from 30 to 50 and all it did was increase or decrease the frequency of the loping.
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