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I have this frustrating issue going on with my 2000 Pro Air Nautique, PCM 5.8l HO. The engine simply dies while we are just cruising right along. Then it doesn't want to start for several minutes. It turns over and over and over but won't start. But after a few minutes it does. So we start heading back for the dock and it dies again within a minute or two and the cycle repeats itself. Funny thing is, it'll run forever at idle and also while on the trailer at any rpm with water running through it. Seems to be only while under load that it happens. Oil level and pressure are good. Engine temps perfectly normal. Kill switch has been bypassed. I'm thinking fuel pump but I'm no pro. Any thoughts? Much appreciated.
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GT40? Carb version of 351W HO? What is the number on the metal tag at rear of engine? That info will help.
JQLast edited by Jonny Quest; 07-18-2021, 11:27 AM. -
Thanks, JQ. Yes, it's a fuel injected GT40.
Model: PLP PRR12 M
Serial: 400143 followed by 4Y44301 58L
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Sounds like the low-pressure (LP), high-pressure (HP) fuel pumps or FCC is acting up. FCC=fuel control cell. You can run a few searches and find lots of good info on CorrectCraftFan.com and this site on this subject.
If one or both Fuel Pumps are failing, the FCC can’t supply enough fuel to the engine at higher demand rates. Another known FCC issue has to do with the fuel line that feeds the HP pump. The HP pump is located inside the FCC and the fuel line feeding it can deteriorate and fail. Also, there is a fuel filter inside the FCC that could be clogged. It's a good idea to change out the filter regularly. NautiqueParts.com has an FCC filter kit that comes with the filter and O-rings.
have you had the FCC open before? If not, they can be quite stubborn to open / remove. On mine, I had to borrow a BIG pipe wrench. I wrapped several layers of duct tape to protect the FCC and then used the pipe wrench. When reinstalling the FCC outer case, put a little anti-seize lube on the threads.
JQLast edited by Jonny Quest; 07-18-2021, 04:26 PM.Comment
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Check fuel pressure while driving a tester is in the $30 range easy to do screws onto the fuel line. Should be between 28 and 34 psi if I remember right.Originally posted by Camel_Towboat View Post
Get a pro boss gt40 service manual google it pdf is widely available it's a good read.
If fuel pressure is ok test for spark the tfi module likes to dail under heat.
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Thank you very much for the tips. The low pressure fuel pump buzzes to life when the ignition is first turned on, so I'm thinking that it is not the problem. I'm going to buy a high pressure fuel pump and the filter kit, plus the fuel pressure gauge and see where that gets me. I still have this nagging feeling that it could be related to the kill switch. Even though mine is bypassed, is there any chance that the issue could be at the other end of its wires? Again, I really appreciate the help.Comment
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If it was your kill switch, I don't even think it would crank... Maybe I am wrong. Also, just because you hear the LP fuel pump when you turn the key, doesn't mean it's not bad.
If I remember right, the GT40's have 8 individual coilpacks for the cylinders. They were known to go bad after awhile and do similar things like you describe. Maybe another will chime in but my old brain has issues remembering 20 years ago lol. Best of luck.
Also, if you're using regular ethanol gas, that probably has corroded your high pressure pump. I had a 2004 SAN and the HP pump started having issues. Pulled it and it was corroded to ****. PCM said it was due to the ethanol.Comment
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I thought this model would still have a distributor and single ignition coil, does it?Originally posted by shag View Post
I'm a big fan of troubleshooting before throing parts.
Get a ignition tester as well than check both fuel pressure and ignition and go from there.
The kill switch disables spark the engine will still turn over. To bypass it all you have to do is to put the 2 wires going to it together.
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Your low pressure pump can make the priming noise and not be working properly/adequately.Originally posted by Camel_Towboat View PostComment
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On that era of boat it most certainly would. On these boats with the kill switch disconnected, the engine will crank and briefly start. It was a maddening problem that sent many boats to the mechanic for something very simple. It "just didn't make sense" that the engine would even try to start with the kill switch disconnected.Originally posted by shag View Post
-Charles
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Thanks again everyone for your input. I’m going to get this figured out. I found some other posts that referenced the same symptoms and they found it to be a clogged anti-siphon valve back at the fuel tank. I will check that also.
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UPDATE: Fuel pressure test with engine running = 36 psi. Replaced LP pump anyways, replaced fuel pickup line and antisiphon, then went for a drive. All was great for 30 mins or so. Stopped and started engine a few times in between with no issue. Then shut engine again off to float down the river. This time it didn’t want to start. It turned over just fine but didn’t ignite. Waited several minutes and it fired up and we made it the two miles or so back to the dock with no further issues. Back home, I removed the fuel control cell and inspected the HP pump. It and it’s short fuel line looked fine. I also replaced the fuel filter inside the FCC. The old one had a bunch of what looked like coffee grinds in it, but not enough to clog the filter.
I’m now thinking my problem is electrical. When my kill switch was still functional last summer, there were numerous times when we would be cruising on the river and the boat hesitated and sputtered, but I quickly pressed the kill switch in harder (old flimsy lanyard) and it picked right back up and kept cruising. I thought bypassing the kill switch would fix that issue, but apparently not. Today I took the side panel off and followed its wires and found nothing amiss. Maybe something is going on in the ECM?
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It’s looking like it’s the engine stator, the PIP (Profile Ignition Sensor), or crankshaft position sensor inside the distributor.
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Everything that I have read indicates that changing the distributor and the two fuel pump relays should solve my problem. I also read about making sure that the new distributor gear is made out of the same metal as the original. So is this replacement a simple plug and play, or do I need to worry about causing timing problems? That would be where I draw the line, admit my limitations, and take it to a shop. Any further advice is much appreciated.
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I’m running into something similar lately. No misfires or sputtering. My boat will randomly stall at various RPMs. It usually starts right back up. Once in a while it won’t turn over or crank at all. I’ll try a few times then it will crank and start right up. Kill switch is bypassed. It first stalled a few weeks ago right when I hooked up a pump to the battery to fill a fat sack. Not sure if that was a coincidence or not. The no crank has been going on for a few summers and the stalling is new.
You think they are related? Did you ever resolve your issue?
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