GT40 quit but still starts when cold
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=49972
Printed Date: November-22-2024 at 11:11pm
Topic: GT40 quit but still starts when cold
Posted By: MurphyCO
Subject: GT40 quit but still starts when cold
Date Posted: July-04-2021 at 12:33pm
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After 5 very successful and fun years, my 99 Air GT40 finally is giving us grief and my wife is not so trusting. (our lake has little traffic often and cell phones don't work....blessing and curse) Anyway, the engine started and ran great all season till yesterday when it bogged down and then quit. We were towed in and put it away for the evening. Next day, started right up. Filled the tank at the marina (it was only down a quarter or so) running great. Tried to start it two hours later and no luck at all. Sounded like a fuel issue, and I read that vapor lock can happen so I loosed the fuel filler cap. (was a bit tighter than usual, but this didn't work. Tried again today and once again starts right up and runs great, but I really want to figure out the issue so mama will trust the boat again. I ordered a fuel filter for the FCC (not sure if I replaced it 5 years ago when I found a broken wire in the HP pump) so I will certainly do that. I tried to find a part# to replace the low pressure filter, but I can't seem to find that on NP anywhere. Any suggestions? Gary
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Replies:
Posted By: MrMcD
Date Posted: July-04-2021 at 12:45pm
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Start with verifying your fuel pressure while it is running. Leave the gauge hooked up and run the boat, if it dies again check your pressure while it is dead. Cycle your key on and off which should activate your fuel pumps with each time the key is turned on, it will only power the pumps for three seconds with each turn of the key if the engine does not start. Pressure should be around 40 psi. ------------- |
Posted By: MurphyCO
Date Posted: July-04-2021 at 12:52pm
Thank you! I have a fuel injection pump test kit; do I test at the relief valve / test point on the FCC body? Allen screw? |
MrMcD wrote:Posted By: Gary S
Date Posted: July-04-2021 at 12:59pm
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You have a 22 year old boat-who knows what was done to it before you owned it. Unlike wine, things don't get better with age. Like Mark says above check fuel pressure. Then think about a replacement low pressure pump if it has never been changed,a Carter P4389 is a good alternative to the PCM marked up price. You just need to cut and splice the plug from the old pump. Change your old fuel lines and check your anti siphon valve. There is a filter in your low pressure pump you could check there are no available internal replacement parts. ------------- 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: Gary S
Date Posted: July-04-2021 at 1:08pm
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Low pressure pump maintenance -       ------------- 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: MurphyCO
Date Posted: July-04-2021 at 1:16pm
Thanks Gary, I have changed a good many things a few at a time (plugs, wires,belts, hoses, HP fuel pump, water pump, upgraded alternator, etc) but I have not addressed the low pressure pump, Will take your advice and do that as well, and the anti-siphon valve. |
Posted By: Gary S
Date Posted: July-04-2021 at 1:25pm
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I bit the bullet this year and replaced my already 26 year old hoses and checked my valve as well. Have not had any trouble but just wanted to check. I was able to get the correct hose at O'Reilly's in a day. My LP pump was changed 8 years ago so I'm not worried about it but I might get a spare just to have one. ------------- 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: cboland
Date Posted: July-04-2021 at 2:54pm
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I also agree this could be a low pressure pump failing. Mine did this as well. It would work fine when cool, but not pump anything when hot even though you could hear it power up. Check your fuel pressure with a gauge to confirm. I replaced with the Carter mentioned above. Works like a charm. ------------- Bud 1999 Sport Nautique |
Posted By: MurphyCO
Date Posted: July-06-2021 at 9:30am
As suggested I took the LP pump off and cleaned it up. The screen was very clogged and scrubbing it with carb cleaner and acetone removed a lot of gunk from it. Cleaned the impeller blades and pump body as the maintenance guide said and reassembled. Boat started up immediately and ran very strong for 10 minutes, high and low speed. No issues. Let the boat sit all day on the lift and returned 3 hours later. Warm day, 85 or so. Boat refused to start at all. From everything I read on here the LP fuel pump seems to be a likely suspect; I guess since the electric motor is sealed there could be a breakdown when the temperature gets up? Hate to waste time and money switching out parts till it is fixed. Seems like something very temperature sensitive might at least limit the possible suspects? Any suggestions greatly appreciated. Gary
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Posted By: Gary S
Date Posted: July-06-2021 at 10:09am
I think your best bet is replacement then- you don't have any idea to it's age,they do have a history of failing. You have done all you could to it. They can be found on ebay for around 80 bucks rather that the 200 with PCM's name on it.
------------- 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: KENO
Date Posted: July-06-2021 at 12:21pm
Here's a picture from a recent thread showing where the schraeder valve is
Since you have a gauge, now you can check pressure when it won't start then you'll maybe know where to throw money next instead of guessing.
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Posted By: MurphyCO
Date Posted: July-06-2021 at 5:21pm
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Posted By: MurphyCO
Date Posted: July-06-2021 at 5:24pm
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https: http:////www.summitracing.com/search/part-type/fuel-pumps?fr=part-type&SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=carter%20P4389%20fuel%20pump" rel="nofollow - //www.summitracing.com/search/part-type/fuel-pumps?fr=part-type&SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=carter%20P4389%20fuel%20pump
Summit Racing has this in stock and I drive by one of their locations often. I understand I would only need to splice the wires to fit the plug on the old one? Correct? |
Posted By: Gary S
Date Posted: July-06-2021 at 5:50pm
Yes  You can do this using the type of crimp connectors that have adhesive in them or what someone did in my boat, cut the wire plugs off and splicing direct. I have new plugs to replace mine so you know where I'm going. Just need to get a crimper for deutsch plugs. ------------- 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: MrMcD
Date Posted: July-06-2021 at 6:32pm
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As already advised, check the pressure before buying any new parts. Those old Carter designed low pressure pumps are tough and last. They powered nearly every Motorhome for years till those same Motorhomes switched to fuel injection or diesel. Sometimes they need to be cleaned if the pump sits for long periods between use but other than that they are reliable. If your fuel pressure gauge shows low pressure that will start directing you what to work on. Warning do not test the fuel pumps dry, they are fuel lubricated and will burn up in just seconds of dry use. It is so tempting to hook up the power and test one before install and that is fine if you supply fuel to the inlet so it gets lubricated while you test. ------------- |
Posted By: MurphyCO
Date Posted: July-07-2021 at 7:49pm
So today I found time to check pressure on the fuel rail per the suggestion of many.  I cycled the pumps a couple times, and the pressure read 38-39 psi. (not running) After 2 minutes, pressure was 35 and at a10 min about 28. I started the engine and the pressure stayed around 35 pretty consistently. I was not able to duplicate the non-start since that takes a few hours after I run it some, and then leave it on the lift with the cover closed. Boat tries to start but will not. Any suggestions? Gary |
Posted By: JayG80
Date Posted: July-07-2021 at 8:05pm
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When the boat will not start, feel the coil and see if it is hot. Also, be aware that the FCC has a retrofit kit. Unrelated to your concern. https://www.nautiqueparts.com/product/repair-kit-for-fuel-control-cell-fcc/" rel="nofollow - https://www.nautiqueparts.com/product/repair-kit-for-fuel-control-cell-fcc/ ------------- 2007 Ski 2002 Ski |
Posted By: Gary S
Date Posted: July-07-2021 at 8:54pm
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Not an oil filled coil though so I don't know if it applies and even if it was oil filled would it not need an external resistor or a resistor wire? Not sure it has one of those either. I'm still thinking low pressure pump because of their failure rate in this application. Your boat is 22 - mine had been replaced under 18 years and 300 hours. I know Quinner's '05 206 with a Chevy needed a pump change at one of the Green Lake events and that pump for sure was not more than 10 years old at the time. Might have to keep running around with the gauge connected up until the symptoms occur and go from there. ------------- 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: MrMcD
Date Posted: July-08-2021 at 12:00am
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Leave the fuel pressure gauge hooked up and tie it to something so it does not do damage or get damaged. Go ski and play in your boat. If the problem comes back you can do a very quick check on your pressure at that time, you could also see if it is losing pressure while parked hot. Your first pressure drop test is fine but see what it does out on the water, it may change when hot. Good Luck. ------------- |
Posted By: MurphyCO
Date Posted: July-08-2021 at 7:46am
Actually I replaced that 5 years ago when the boat wouldn't run after I purchased it and trailered it home. I also doubled ordered that repair kit by mistake and need to gift it to someone on the site. Boat started immediately after that repair and hasn't missed a beat since. (till now) I honestly believe the LP fuel pump is the culprit because when it quits it just sounds like a fuel issue.
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Posted By: MurphyCO
Date Posted: July-10-2021 at 9:10pm
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UPDATE Fuel looked good, no water. Boat started up and ran strong, as suggested I left the pressure gauge attached and pressure was a constant 34-35. Let the boat sit hot for 3 hour and it started up with no issues. I believe the LP pump was the issue; seems when it got hot it failed. I'll run some more tomorrow just to see if everything seems ok, but it appears this was the fix, Thanks for all the suggestions! Gary
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Posted By: MurphyCO
Date Posted: July-29-2021 at 10:56am
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Thought I would update for anyone with similar issues; after several weeks and lots of starts, hot and cold, I believe the issue is resolved. Boat runs strong. Apparently the low pressure pump was the issue. Thanks for all the suggestions and assistance. Gary
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Posted By: gun-driver
Date Posted: July-29-2021 at 3:10pm
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Gary, Glad you got it figured out
 Sent youy a PM. |
Posted By: MurphyCO
Date Posted: August-24-2021 at 9:14am
Posted By: MurphyCO
Date Posted: August-24-2021 at 9:16am
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Wanted to let everyone know...after replacing the LP fuel pump the boat continues to run exceptionally well. No issues for several weeks and lots of hot and cold starts. I believe that was the issue, and the one I got from Summit Racing was very easy to install. Gary
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Posted By: KENO
Date Posted: August-24-2021 at 1:34pm
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How's that alternator alignment issue treating you? It must be time for an update on that
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Posted By: MurphyCO
Date Posted: August-24-2021 at 1:42pm
Unfortunately no solutions for the alternator yet. I may have to limp around with backup belts till winter take-out and work on it this winter. NP says they are working on a solution but nothing yet. The bracket I ordered was NLA after I placed the order and called, even though the website took the order. I wasn't charged, however. |
Posted By: Gary S
Date Posted: August-24-2021 at 2:03pm
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Good to hear all is well on the fuel problem,a job well done!
------------- 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 |