Intermittent 95 super sport nautique gt40 surge un
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=41528
Printed Date: October-06-2024 at 10:18pm
Topic: Intermittent 95 super sport nautique gt40 surge un
Posted By: kylem428
Subject: Intermittent 95 super sport nautique gt40 surge un
Date Posted: July-17-2017 at 12:25am
Hello all so as the title says I'm having an intermittent problem so it's challenging to re create and diagnose. When it happens, the Engine starts and idles fine and Runs well up to 2500 rpm or so then when I go to 3000 or more it will surge down like 3-400 rpms, recover, and surge again. I can give more throttle but this happens throughout the upper power band and won't clear itself up until I re start the engine. After I turn off the boat, and re-start its fine and we can wakeboard for a bunch of sets weighted with no trouble. This has happened on 2 or 3 occasions. I originally thought bad gas, I also checked the fuel filter that I replaced last fall and it is clean. I think it is electrical related to the fuel system but not sure where to start. Ecm and fuel relay would be a good first guess but after that, what? Anything else I should be checking? Thought about anti siphon and fuel pickup but that doesn't seem to make sense given I can restart and clear the issue up. Engine had a full tune up last summer (cap rotor, plugs, wires). When my fuel filter was replaced my high pressure pump was whining but the new filter solved it so I do t think it's a fuel pump issue.
Thanks for for your help!
Kyle
|
Replies:
Posted By: Gary S
Date Posted: July-17-2017 at 1:41am
I was told years ago by our fleet mechanic at work that if you run a restricted fuel filter long enough and then change it the pump will fail. Keep in mind this was a vehicle which only has one pump anyway. Something to do with the pump working hard and loading itself and after the filter change the armature shifts back and soon fails. I worry that your pump was making noise. Do you have the 1995 non FCC version? Ever change the LP pump? How many hours? My LP pump didn't even make 300 hrs before it was replaced.
-------------
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: kylem428
Date Posted: July-17-2017 at 9:46am
Yep 1995 non FCC so I have both the lp and hp pumps. Boat has 700 hours as of yesterday - 20 of which are post fuel filter and hp pump whine. I'd be surprised if either of the pumps were ever replaced. Since the hp pump is NLA, would you make the switch to an FCC if I am going to be needing a new pump of sorts?
Thanks!!
Kyle
|
Posted By: Gary S
Date Posted: July-17-2017 at 11:38am
Well that is an alternative but it's over 800 bucks for that kit. Then since they are over 20 years old you might want to change the feed and return fuel lines from the tank as well. And since it's a vdrive you'll find that where the fcc fits, that space is occupied by the strainer and trans cooler so all that has to be moved over to the other side where your fuel pumps now sit with new longer hoses to fit. I found out all this because I'm in the process of collecting all the parts needed rather than buying the kit,just so I have it on hand if and when mine goes. If your LP pump is engine color,it's the original pump. I'm no expert but I would suspect that LP pump. If it was mine I'd get a Carter P 4389 marine pump for under 60 dollars vs the oem PCM Carter built pump at 212.00 but that's up to you. Some will say you should check your fuel pressure but frankly I don't see how that will tell you what pump is bad ie if the LP pump is not providing fuel to the HP pump that pump will not build pressure and you think that pump is at fault. The HP pump formally making noise bothers me but that fact that the engine runs kinda leads me to believe that it's the supply pump and the fact that so many of them have gone out with relatively low hours.
-------------
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: kylem428
Date Posted: July-17-2017 at 1:14pm
Thanks Gary. I'll look in to the carter lp pump you suggest. In the meantime, is there a screen in the lp pump I can pull and check for blockage/ restrictions?
Finally, if/when the HP pump goes, isn't there a conversion I could do with another carter hp pump? I was doing some reading when mine was whining and it seems though the oem one is NLA, you can get a similar spec hp marine fuel pump with the same electrical plug, but the only difference is that it has 1 input line instead of the 2 inputs the OEM pump has, so a little effort would be required to T in to it but I think that would be an alternative to a full FCC conversion wouldn't you think? Oem replacement was a 2-input carter p60962 but you can get a single input port carter p61171 or p5000 that may do the trick? There was a post in the Malibu crew about this since indmar used the same 2-input pump for quite a while - people are capping that 2nd feed line since it was a return line to try to prevent vapor lock. I suppose that is also an option instead of t-ing in to the input.
Thanks!
Kyle
|
Posted By: Gary S
Date Posted: July-17-2017 at 3:02pm
Yes there is, I have not done it though. Those 3 nuts that hold the pump to the bracket are studs you can remove, the top plate comes off. I think there is a screen and you can see the vanes of the pump. Don't know what gasket is under there though or where you'd get a new one if you damage it. Paul, gun- driver on here has used a single inlet HP pump and plugged the return line. He could answer any of those questions
-------------
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
|
|