78 ski nautique issue
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=40881
Printed Date: April-23-2024 at 9:33am
Topic: 78 ski nautique issue
Posted By: dustyb
Subject: 78 ski nautique issue
Date Posted: April-17-2017 at 10:55pm
| I'm having a problem with my 78 ski nautique after it warms up. When I first put it in the water it's fine until 45 mins to an hr then it starts studderings. I can back off the throttle and it clears up but if I give it gas again it starts studding again. It acts almost like it's running out of fuel like maybe a vapor locking issue. I don't think my problem is vapor lock since it's not overheating or anything. If it was a carb issue it looks like to me it would be doing it even when it was cold since I have my choke unhooked. It's acts more like a fuel issue than a ignition issue since I can back off the throttle and it quits. Do any of you guys have an idea? Or give me an idea on where to start? |
Replies:
Posted By: 8122pbrainard
Date Posted: April-18-2017 at 1:04am
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Check your anti siphon valve for debris. T a pressure gauge into the fuel line between the pump and carb. Loosen your fuel tank fill cap to make sure you are getting enough air into the tank. ------------- /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: Gary S
Date Posted: April-18-2017 at 1:16am
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http://www.jalopyjournal.com/forum/threads/95-of-all-carburetor-problems-are-ignition.968986/" rel="nofollow - Interesting article just ignore the voltage they are talking. I would check your voltage at your coil and check to see if you have a ballast resistor. Have you changed coils lately? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: 63 Skier
Date Posted: April-18-2017 at 1:20am
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Check the items Pete suggested above. You want to find out if it's fuel or ignition causing the problem, could be either. Since you can smooth it out by throttling back, and assuming you can repeat the process, I'd lean toward fuel being the issue. You could have an older fuel line that is collapsing a bit under suction, the fuel gauge would indicate that. While you are at it I'd pull spark plugs and see what they look like as well. ------------- '63 American Skier - '98 Sport Nautique |
Posted By: dustyb
Date Posted: April-18-2017 at 4:05pm
| I'm thinking it's more of a fuel issue. I just put new plugs and wires on it, I'll install a fuel pressure gauge and see what it reads and go from there. |
Posted By: SN2001_1984
Date Posted: April-18-2017 at 6:11pm
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x2 on Pete's comment - had the same issue with my '84 and the 90 degree fitting/valve on the top of the tank were loaded full of junk. Another trick is to run a line from the fuel pump to a 5 gallon container of gas and run it, see if eliminates the issue. that way you know its in the tank or the line or filter. ------------- 1984 Ski Nautique 2001 :: 351 Original factory ordered color combo from Silver Spray Sports: Fenton MI |
Posted By: dustyb
Date Posted: April-18-2017 at 8:01pm
| Well one thing that makes me think it's not the anti siphon is my fuel filter stays full of fuel. If the valve was stopped up I wouldn't be getting fuel to the filter. I pulled the filter out going into the carb and see trash in it. I'm going to clean it out and go from there. |
Posted By: 8122pbrainard
Date Posted: April-18-2017 at 8:50pm
Dusty, I'd say the filter looks full because you aren't sucking air! Get that gauge installed. BTW, what filter are you talking about? Hopefully it's not one of those inline filters designed for outboards. Post a picture so we can check it out. We sure don't want you driving a bomb around the lake!! ------------- /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 < |
dustyb wrote:Posted By: dustyb
Date Posted: April-18-2017 at 10:04pm
| I forgot to mention I did check the fuel pressure and it was 5lbs and never changed even when it started spuddering. |
Posted By: PKB1023
Date Posted: April-18-2017 at 10:37pm
| I had the same problem with a car back in the late 70s. The condenser would act up after it got warm. Ran great when it was cool. Hope this helps. |
Posted By: dustyb
Date Posted: April-20-2017 at 7:27pm
| Ok I was wrong about the fuel pressure. It's good until I start giving it gas. At full throttle I have zero fuEl pressure and it dies but can let off and it'll pick back up. Haven't che ked the valve yet, I'm going to do that and if it's clear it must be the fuel pump |
Posted By: 63 Skier
Date Posted: April-20-2017 at 7:42pm
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That's good news, means you've found the problem! If the anti-siphon valve ends up being ok, don't rule out a collapsing fuel line. Before replacing the fuel pump I'd run it on a short length of fuel line into a gas can like Denny (SN2001_1984) said above. That would tell you if your fuel pump is ok and it's the fuel line or valve causing the problem. ------------- '63 American Skier - '98 Sport Nautique |
Posted By: 8122pbrainard
Date Posted: April-20-2017 at 9:44pm
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Dusty, Yes, it's good news you are narrowing down on the problem. I'm glad you got that gauge installed. What about that filter. I wasn't joking about the ones designed for outboards.
------------- /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: quinner
Date Posted: April-20-2017 at 9:48pm
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The anti siphon is pretty easy to get to and check, my 77' way back when had the same exact symptoms and it was a clogged anti siphon. Betting that will be your answer. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1143" rel="nofollow - Mi Bowt |
Posted By: dustyb
Date Posted: April-20-2017 at 10:50pm
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It was the valve Got it cleaned up and running good. I have a slight hesitation from dead stop to full throttle I'd like to get out. I adjusted the air screws on my carb using a vaccum gauge so it should be set pretty dang close on that part. What else should I check to get that hesitation out? As far as the filer it was just an automotive in line filter but I took it off when I put the gauge on, I'm going to just run a new line from the pump to the carb with no filter. |
Posted By: 63 Skier
Date Posted: April-20-2017 at 11:10pm
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Might be accelerator pumps. Look down the bores (not running) and see if they are squirting evenly. ------------- '63 American Skier - '98 Sport Nautique |
Posted By: dustyb
Date Posted: April-20-2017 at 11:19pm
| Yes they are squirting like they should. I adjusted the linkage on the accelerator pump where there was no play and it wasn't pressing down like it's supposed to be. Should the pump cam be in the number 1 or 2 hole? I tried both and seemed to be better in the 2nd hole |
Posted By: bwinn
Date Posted: April-20-2017 at 11:30pm
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