gt40 running rough |
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Mike9812121298
Senior Member Joined: March-24-2017 Location: Seattle Status: Offline Points: 139 |
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So I found this when googling the issue. Someone else was saying there car will only idle at 60 degrees timing.
#16 B4Ctom1's AvatarB4Ctom1 , 02-20-2002 09:55 PM during a bench race session of car builders and racers I posed this question in the form of a pop quiz, "when you try to start a car and the thing will not run without a bunch of advance and the timing light reads like 50*-60*, what is generally the problem?" I got a resounding answer of, " a dist that is 'stabbed' 180* out." when I posed the question of the timing light reading and why it reads that way I got everything from a, "it just does..." to a, "when the earth's orbit..." ps: no prob 87_ta, its cool |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Online Points: 10644 |
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Not hard to find the thread with some Google assistance.on "thirdgen.org" that you got this from
An excellent example of why you shouldn't believe everything you read on the Internet. |
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Mike9812121298
Senior Member Joined: March-24-2017 Location: Seattle Status: Offline Points: 139 |
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Here's at idle it's about 40
https://youtu.be/5ZPowF2gn1c Here's at 3k rpm https://youtu.be/nIEjp8G5vwI |
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Dreaming
Platinum Member Joined: May-21-2010 Location: Tacoma, WA Status: Offline Points: 1870 |
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Mike - If you get stuck, I have heard that Pacific Nautiques is a quality shop. I have never used them, but have friends who do. I am not sure how a distributor could be stabbed in 180° out on these machines, as mine twists the whole way around without any resistance. if a GT-40 is position sensitive, it would be worth re-doing it, set to TDC on cyl 1 and re-stab the distributor where you feel it needs to go and re-try. my GT-40 experience is next to zero, so YMMV.
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Mike9812121298
Senior Member Joined: March-24-2017 Location: Seattle Status: Offline Points: 139 |
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i took it out saturday and it ran pretty good. i was out there for about a hour and had no issues. pulled hard off the line, i filled up 1000 pounds of fatsack and it would still pull out of the water with no issues. i dont know maybe i put the f150 balancer back on the engine would i should have put the gt40 one on so its throwing the marks off
i really try to stay out of shops, but i have heard good things about them |
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Dreaming
Platinum Member Joined: May-21-2010 Location: Tacoma, WA Status: Offline Points: 1870 |
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Me too, just noting that they are a place I would go if I got REALLY stuck. Nice that it ran well! Balancer shouldn't make that much of a difference, if the 0/TDC lines up in the right place. |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Online Points: 10644 |
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Back on the 17th you mentioned that TDC lined up right so it's not a balancer issue. What's your timing if you check it running down the lake at 3000 rpm or so? Or better yet, what is it at every thousand RPM running down the lake? |
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Mike9812121298
Senior Member Joined: March-24-2017 Location: Seattle Status: Offline Points: 139 |
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i didn't make note of that timing while driving down the lake last time i took it out but by going off my last video it shows 20mph at 2,500prm and about 34mph at 4,000rpm.
this is also with the acme 480 propeller. If i get some time tonight ill take it out again and make better note of the speed vs rpm and timing marks yeah i checked the tdc and that was on the mark for the balancer. im guessing its something i did wrong while putting the engine back together |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Online Points: 10644 |
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I think those timing numbers under load every thousand rpm's will be really useful to figure this out.
Key words here are..................under load |
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Mike9812121298
Senior Member Joined: March-24-2017 Location: Seattle Status: Offline Points: 139 |
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Mike9812121298
Senior Member Joined: March-24-2017 Location: Seattle Status: Offline Points: 139 |
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So before I went out I moved the timing back to 10 put the spout back in, rev up in the drive way and it sounded good. Took it for the water test and it ran good. I don't really know what changed from last time trying to run at 10 compaired To now. Prob screwed up the engine in the process. It ran good on the water but I noticed oil psi was dropping at idle to 10 or so. I'm gonna swap out the oil and filter tomorrow and see if that helps
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Online Points: 10644 |
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You can take this any way you want Mike but what is your problem with listening to people who are trying to help.?
Is it so hard to time the thing the way it's meant to be ? You're just randomly moving your timing all over the place, you never checked it under load, remember it's fuel injected and the timing is controlled electronically and load has a BIG part in that signal that's gonna come from the computer. You don't have a clue what your timing is, running down the lake but who cares, just keep running it This reminds me of your bondo repair, ask advice then ignore it over and over till somebody (more than one person) picks on you and your methods enough that you decide to listen and redo it. I'm just gonna sit back and enjoy the circus now |
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lewy2001
Grand Poobah Joined: March-19-2008 Location: NSW Australia Status: Offline Points: 2234 |
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From and old thread when I was doing some prop testing.
The GT40 is pretty conservative with ignition advance. Timing No load Running on Water 700rpm 8 degrees 700rpm 8 degrees 1000rpm 11 degrees 1000rpm 11 degrees 2000rpm 20 degrees 2000rpm 27 degrees 3000rpm 28 degrees 3000rpm 31 degrees 4000rpm 30 degrees 4000rpm 30 degrees With the GT40 you can only set the static timing the rest of the time the GT40 ECM adjusts the timing depending on input from all other sensors it has a range of 25 degrees from memory that it adds to the static timing from the table in the ECM. Base timing per manual is 5 deg BTDC with Spout disconnected and engine at operating temp. I have played around with this and actually have tried other settings up to 10 BTDC. I had mine set to 8 degrees with the GT40 ECM. Tried this setting on another GT40 at GL and could hear a slight ping so set it back to standard. The GT40 also has knock sensor that will retard timing if detected. |
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If you're going through hell, keep going
89 Ski <a href="http://www.correctcraftfan.com/diaries/details.asp?ID=5685" ta |
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Mike9812121298
Senior Member Joined: March-24-2017 Location: Seattle Status: Offline Points: 139 |
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so over the weekend i did some testing on the boat, found that i was getting 12v to the lpfp. I disconnected the hpfp and noticed i couldnt hear the lpfp prime. i also did a water test by disconnecting the lpfp and took off and watched it want to bog down after 3k rpm. the same thing happened with the lpfp hooked up
i replaced the lpfp and took for a water test, boat runs great up to 5k now. Thanks for all the help |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4945 |
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So, a new low pressure fuel pump was the fix?
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tryathlete
Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797 |
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That's what mike is saying. Another LPP failure/slow
Death causes nothing but trouble. |
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gun-driver
Grand Poobah Joined: July-18-2008 Location: Pittsburgh, Pa Status: Offline Points: 4112 |
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That has nothing to do with what was going on with the timing, that doesn't change with a fuel pump????
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Mike9812121298
Senior Member Joined: March-24-2017 Location: Seattle Status: Offline Points: 139 |
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no idea but timing is set to 8 advance. i also changed the oil now oil pressure is reading where it should. im gonna take it out in the next couple days and give it another run.
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gun-driver
Grand Poobah Joined: July-18-2008 Location: Pittsburgh, Pa Status: Offline Points: 4112 |
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Why not set the timing to 5* like its supposed to be and see how it runs?
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Paul, It seems to me that we have tried to offer direction many times and it has rarely been taken. It reminds me of this: "The carronade, hurled forward by the pitching, dashed into this knot of men, and crushed four at the first blow; then, flung back and shot out anew by the rolling, it cut in two a fifth poor fellow... The enormous cannon was left alone. She was given up to herself. She was her own mistress, and mistress of the vessel. She could do what she willed with both." I've given up to "herself"! |
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