Transmission slipping or something else?
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=47932
Printed Date: April-28-2024 at 4:14pm
Topic: Transmission slipping or something else?
Posted By: Crmaverick
Subject: Transmission slipping or something else?
Date Posted: August-17-2019 at 6:34pm
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I’ve been having an issue that feels like cavitation or slipping in my 84 2001 with the HO 454. Trans fluid is new and topped off with dextron vi synthetic. Prop is a new Acme 431 The weird thing is that I can hole shot it wide open and the thing pulls hard with no “cavitation/slipping/high reving symptoms”. The issue only shows up when you try to push it past 4000ish rpms and then the tach jumps to about 6500 rpms Trans fluid smells fine and not burnt. Below is a video showing the issue. Any ideas on this guys? How could the tranny only slip on high rpms but not during a hole shot? https://drive.google.com/file/d/1Hl-jq_ON8-BAm3yd-SK1pXSomlmV98nA/view?usp=drivesdk" rel="nofollow - https://drive.google.com/file/d/1Hl-jq_ON8-BAm3yd-SK1pXSomlmV98nA/view?usp=drivesdk |
Replies:
Posted By: 8122pbrainard
Date Posted: August-17-2019 at 6:45pm
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Chris, Sounds more like cavitation to me. Is that with your new 431 prop? What's the cup on the 431? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: KENO
Date Posted: August-17-2019 at 6:56pm
In my best English I ain't never seen nuthin' that could break the prop loose at 40 or so mph  Cup is .080 inches Is that ATFplus4 fluid Mav? |
8122pbrainard wrote:Posted By: Crmaverick
Date Posted: August-17-2019 at 7:16pm
ATF dextron VI synthetic Had the same issue with the old prop for those that didn’t see my other post |
Posted By: RealDeez
Date Posted: August-17-2019 at 7:28pm
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Sorry to jump my noob self in where I likely don't belong but could there be an issue with the hull that would cause cavitation at higher speed where it might not at low speed? Just spitballing. ------------- Lake James, IN 93 Sport Nautique |
Posted By: Crmaverick
Date Posted: August-17-2019 at 7:35pm
That’s a good point, everything with the hull checks out, all fins are straight and no hull damage |
Posted By: KENO
Date Posted: August-17-2019 at 8:21pm
Everybody was a noob at one point Keep jumping in, it's a forum |
Posted By: KENO
Date Posted: August-17-2019 at 8:48pm
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Having seen the boat yesterday, like Mav says there's nothing wrong with the hull Per a phone conversation, there was a question of whether the ARE shaft could be slipping inside the coupler so he put a couple of magic marker marks , one on the coupler and one on the shaft and they stayed aligned. That would have taken a broken or missing key to let that happen, so it seems that the coupling is OK Quite a few people use Dex 6 synthetic ATF without issues, but how long has that been in there? Was it changed after you first had the issue? Can you go from zero to 4000 rpm's and stay there for say a minute with no problems ? If you punch it from a dead stop does it get to 5000 rpm and around 50 mph or does it start having issues at a lower rpm before getting there? |
Posted By: Crmaverick
Date Posted: August-17-2019 at 9:00pm
The trans oil is fresh, I didn’t change it after the first test run when I noticed the problem, fluid is a couple weeks old. I can go from 0 to 4000 wide open and then let off and maintain 4000 all day with no problems. The issue will pop up when I open the throttle around 4000 rpms. |
Posted By: RealDeez
Date Posted: August-17-2019 at 9:03pm
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Another noob post: does it change if you're towing something? ------------- Lake James, IN 93 Sport Nautique |
Posted By: Crmaverick
Date Posted: August-17-2019 at 9:05pm
I haven’t tried that yet, problem happened with two people in the boat and also three people, half tank of fuel both times |
Posted By: KENO
Date Posted: August-17-2019 at 9:11pm
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I think I'd call Joe at FFI marine in Ohio and talk about this with him, since the only thing left to slip is the transmission. His number is below.
Or these guys in the link aren't too far away from you and they've been around a long time http://marinetransmissions.info/" rel="nofollow - link |
Posted By: GottaSki
Date Posted: August-17-2019 at 9:57pm
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Last thing I can think of is put a pressure gauge on the fwd circuit and look at the line pressure while it's happening and see ifs sufficient, or drops. Yeah likely could just be out of friction material ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Crmaverick
Date Posted: August-17-2019 at 10:12pm
That’s a good idea. I ordered some Lucas extreme duty marine atf, I figure it’s worth a shot. https://lucasoil.com/products/marine-products/engine-oil/lucas-extreme-duty-marine-atf" rel="nofollow - https://lucasoil.com/products/marine-products/engine-oil/lucas-extreme-duty-marine-atf |
Posted By: GottaSki
Date Posted: August-17-2019 at 10:24pm
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Chris by friction material, I mean fiber on the plates, not a fluid thing ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Crmaverick
Date Posted: August-17-2019 at 10:32pm
I figured I was thinking maybe if they’re slightly worn the Lucas could help Another thing, the old oil I pumped out was still pink, definitely old oil though by the smell but no burnt smell or discoloring. You’d think that old oil would be discolored and burnt alittle bit by now |
Posted By: 8122pbrainard
Date Posted: August-17-2019 at 10:46pm
Give it a try and report back but, I have a feeling the friction modifier will have the opposite effect. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: 8122pbrainard
Date Posted: August-17-2019 at 10:47pm
+1 ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: TRBenj
Date Posted: August-17-2019 at 11:33pm
| I didn’t hear any wind up that would lead me to think anything’s slipping. I suspect all is well and your tach is lying. Rpm’s didn’t change much by my ears. I would have expected a stronger response from a hammer drop at 40 with a HO 454 if it’s healthy, especially with the 431. |
Posted By: Crmaverick
Date Posted: August-17-2019 at 11:49pm
On that run we didn’t hammer down, did a gradual run up into the 40s, if you watch around 20 seconds you’ll see the tach jump and hear the motor rev up when trying to give it alittle more |
Posted By: gun-driver
Date Posted: August-17-2019 at 11:53pm
| I have to agree with Tim at 6,500 that motor would be screaming. I could run my ‘95 GT 40 up to 55oo and you knew it |
Posted By: Crmaverick
Date Posted: August-17-2019 at 11:59pm
I was thinking the same thing earlier, maybe the tach isn’t accurate, but then I realized I can hear the motor rev up all of a sudden, while seeing the needle jump same time, without the boat pulling as it should for the increase in rpms I’m hearing, although it was still pulling some and not totally 100% slipping as if in neutral |
Posted By: Crmaverick
Date Posted: August-18-2019 at 12:05am
I did check the trans oil tonight, I found some milky condensation on the top of the stick, guessing that can be normal depending on conditions? The oil itself is clear and red. https://drive.google.com/file/d/1yW7rBrZMAYUMjBG_eN_vu__iNfmgg-V4/view?usp=drivesdk" rel="nofollow - https://drive.google.com/file/d/1yW7rBrZMAYUMjBG_eN_vu__iNfmgg-V4/view?usp=drivesdk https://drive.google.com/file/d/1zc7nxoD9oB32dMzmOEua_HWBkNlVJLYr/view?usp=drivesdk" rel="nofollow - https://drive.google.com/file/d/1zc7nxoD9oB32dMzmOEua_HWBkNlVJLYr/view?usp=drivesdk |
Posted By: TRBenj
Date Posted: August-18-2019 at 9:05am
I saw and heard what you are talking about and it sounded like a few hundred rpm increase as the secondaries opened- very much expected (if not a little weak). Ignore the tach and take another video with a WOT run- and gps it (navionics). Your oil pressure looks pretty high and temp looks pretty low in the vid... hopefully you aren’t running the boat at 40+ until you let the engine warm up a bit. How much experience do you have with inboards (especially older ones)? |
Posted By: Crmaverick
Date Posted: August-18-2019 at 12:08pm
Not much mostly just car and bike motors, that temp gauge must be off when I shoot the motor with the infrared gun I’m reading in the 140s. I took the thermostat out a few weeks ago and put in boiling water on the stove, watched it open around 140 then close back up after cooling. The oil pressure I have no idea, I’ve seen hot idle in the 30s to 40. I’ll take another video next weekend. I want to agree with you on the rpms that’s what I had originally thought, to me I feel like the motor has more to give when running at 4500 which might be 3500 in reality. I did rebuild the carb and been messing with the float heights to get it running right. Adjusting the primary float height I had to ignore the sight hole for adjusting because of the motor tilt. (Lowered height until fuel stopped dripping in after shutting motor off) ) I also have 101 needle and seat instead of the 110, no idea if that’s right or not but that’s all the parts store had yesterday and needed new gaskets, and the new 110 in there felt sticky, I wasn’t sure how to adjust the secondary's, so that’s set at the sight hole, but the motor is tilted that way so maybe I’m not getting enough fuel on the secondary's and it’s that delayed sudden kick in I’m feeling? |
Posted By: TRBenj
Date Posted: August-18-2019 at 12:56pm
| Sounds like the secondaries coming in- it’s about the right spot for them to (low 4K rpm range). Is this a vac or mech secondary Holley? |
Posted By: Crmaverick
Date Posted: August-18-2019 at 1:30pm
It’s a mechanical secondary, Holley 800. Do you see an issue with running a 101 needle and seat on the primary? It had a 110 in there. Also how do I know if the float height is adjusted correctly on the secondary’s? |
Posted By: GottaSki
Date Posted: August-18-2019 at 2:16pm
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Ok I heated it with more clarity today To my ear as well, that's not a true 6k, at all I see the speed climb 42 to 45 in short order when you give it some I believe the tach s lying, consider it was constructed for a points system, 37 years ago. And your not accustomed to the symphony of awesomeness the ensues when you lean on on ithis boat and get on it. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Crmaverick
Date Posted: August-18-2019 at 3:28pm
Man that would be ideal, it does sound awesome. I’ll take another video next weekend. I might try raising the float height on the secondaries |
Posted By: KENO
Date Posted: August-18-2019 at 3:33pm
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It looks to me like the tach is reasonably accurate at 4000 rpm and 43 mph on the left speedometer with the 431 Acme and it doesn't act up till he punches it and then it's accurate again after he backs off. Something is making it act up. Have you checked your timing at idle with the new distributor and maybe checked it again at 4000 rpm.? You can do all that in neutral at the launch ramp. If not, a digital timing light with a tach as part of the light to give a double check on the tach would be real handy right now |
Posted By: tryathlete
Date Posted: August-18-2019 at 3:40pm
Everything sounds great to me. Erroneous tachometer reading. |
Posted By: Crmaverick
Date Posted: August-18-2019 at 3:43pm
I set the timing at 10 idle, the distributor manual called for 12 and the PCM manual called for 7 so I set in the middle at 10. I haven’t checked at 4000 yet |
Posted By: KENO
Date Posted: August-18-2019 at 11:02pm
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Well it seems like nobody thinks the transmission is slipping based on a variety of things, but like we talked about, it should slip on takeoff if it's gonna slip. Then again, none of us have been there in person to experience it first hand with you. Any transmission slip I've heard has been noisy, usually on takeoff, sometimes going around a sharp corner while low on fluid and the pump loses suction, but not in a straight line giving it more gas at 40 plus MPH You could see what the transmission guy(s) think, but I'd rule out everything else first, because you probably wouldn't be too happy yanking it out for an overhaul and then having the same problem after it was reinstalled. I'd try a 0 to top speed blast without stopping at 42 like in your video and see how it acts. I'd also have a timing light with a built in tach hooked up for that blast. You could also disable the secondaries in the closed position and see how it runs, you'll lose some RPM's and speed but not a whole bunch. It won't hurt the engine, it just limits how much air and gas can flow through it, limiting the power. Almost hate to mention it but anytime I've had a tach go wacko, it's been ignition related, that's why I asked about the timing and checking the advance at 4000 RPM. The Delco instructions say it should be about 30 degrees total for that EST distributor. Have you checked the plugs to see what they're telling you? If not I'd check them as soon as you can, before heading out with it again. |
Posted By: Crmaverick
Date Posted: August-19-2019 at 1:15am
Sounds good I’ll try all that, the plugs still look new, I guess not enough time to show anything. When I set the timing at the specified rpm in the book, I set it based on my tach reading. Which means if my tach is wrong then I set timing to 10 degrees at the wrong rpm |
Posted By: baitkiller
Date Posted: August-19-2019 at 7:37am
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$20 on amazon buys a laser tach. Buy one, tape the shaft coupling and tape the crank. Go for a burn. simple. ------------- Jesus was a bare-footer............. |
Posted By: JoeinNY
Date Posted: August-19-2019 at 10:58am
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Generally agree with above, from the video it doesn't sound anything like a 6500 rpm big block and in my experience that tach couldn't handle either a DUI or an MSD ignition and give reliable results. Get a modern tach so you know what you are working with. That being said in my experience you can do a few weird things at high speeds with that hull, like pick the ass up out of the water and ventilate the rudder, and eventually the prop - however I don't see that happening with a 431 until the mid 50s. If you are going very fast with more than one person in the boat but the others in the back seat. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: Crmaverick
Date Posted: August-19-2019 at 11:34am
Good idea I have one on order now and will try it out this weekend. |
Posted By: tryathlete
Date Posted: August-19-2019 at 11:40am
| LOL! Speeds approaching mid-50’s and the associated handling characteristics harken to the Jet age when the likes of Yeager and Hoover did our nation’s bidding for us at Edwards AFB. |
Posted By: KENO
Date Posted: August-19-2019 at 12:21pm
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Back to something you asked earlier Mav, I think I'd order a couple of .110 needle and seat assemblies to get back to original size. They flow quite a bit more than the smaller ones like your .101's that you put in |
Posted By: GottaSki
Date Posted: August-19-2019 at 1:05pm
Yeah! Hopefully Mav doesn't report back to us " because we were inverted'" ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: FFImarine
Date Posted: August-20-2019 at 2:31am
| Thank you Keno.... what engine do you have? And what transmission do you have? Besides that the probable cause is low oil pressure not being to able to hold the power at those rpms |
Posted By: KENO
Date Posted: August-20-2019 at 7:59am
| His engine is a 390 ish HP PCM 454 HO in a 1984 SN with a B/W 10-18 |
Posted By: Crmaverick
Date Posted: August-20-2019 at 9:49am
I ordered some .120 needle and seats. The .110 that came with my rebuild kit I believe are to small based on what I read below https://drive.google.com/file/d/1xAE07AqsjiYXHAJrgv0DtcQzkX3sUpnY/view?usp=drivesdk" rel="nofollow - https://drive.google.com/file/d/1xAE07AqsjiYXHAJrgv0DtcQzkX3sUpnY/view?usp=drivesdk |
Posted By: Crmaverick
Date Posted: August-24-2019 at 9:57pm
| I had it out today for a test, still reved past 6 but the boat kept pulling and I saw 50, after adjusting the float height on the secondaries it helped make for a smoother transition up top |