Intermittent No-Start (GT40)

[BrennanK]

When I go to start the boat it willcrank and crank and never catch, as if there is no fuel reaching theengine. So far this has happened two times out of many many successful starts. I have observed, orrather, heard that when this issue occurs there is a lack of fuelpump primping. Usually when I turn the key to the run position priorto starting you can hear the fuel pump do a little buzz. When everthis no start issue occurs that buzz does not happen. Once the engineis running there is no problem, and if that buzz happens beforestarting it starts as if there is no problem.


This leads me to believe that theproblem is the relay for the fuel pump, or something in theelectrical system for the fuel supply. Before I start throwing partsat it I wanted to do a little diagnosis, but I am not sure where tostart.


Do you have any ideas or thoughts as tohow to narrow down the culprit, or any ideas as to what it is?

[HS]

Going based on what I've read here a few times, that is the sign that the low pressure fuel pump is on it way out.

[s_kelley2000]

It sounds like it could be your safety lanyard. Next time it happens try pushing the button in behind the lanyard and see if that causes the pump to run. On my boat if the lanyard button is not depressed it will crank but not engage the fuel pumps.

[spunkie202]

could also be a pcm issue

[DanielC]

If the safety lanyard is off, or the safety lanyard switch loses connection, the engine will run as long as the key is in the crank position.

This thread is a diagram of the relay connections, and helps you identify the fuel pump relay.
http://www.planetnautique.com/vb3/sh...=Fuel+pressure

This is how to check the fuel pressure on a GT-40.
http://www.planetnautique.com/vb3/sh...=Fuel+pressure

In an emergency situation, you can jump pin 30 to pin 87 on the fuel pump relay socket. This bypasses any computer control of the fuel pump relay, the fuel pump should run as soon as this connection is made.

[Connor]

Had this problem about a month ago. Exactly what you described. Turned out to be just the relays. Changed them both and it starts first crank and runs great. I did a lot of research on this when it happened. Do yourself a favor and change the $10 relays (get them at an auto parts store). If that doesn't fix it then check into a new pump. Let us know what it turns out to be!

[BrennanK]

Thanks all for your replies. I wasn't convinced it was the low pressure pump as I would expect some issues other then just starting with that. Next time the issue happens I will try jumping the relay to confirm that is the problem. I am also going to get another relay to keep on hand so if the jumping confirms it I can swap them out.

It might take awhile for it to happen again. It has only been a problem 2 times in around 100+ starts. When it does happen though, it seams to act up for a while. Luckily the only time it stranded us we were 100 feet from to dock, so I could swim the boat back in.

[rodltg2]

Same issue as you earlier this year. It finally just quit starting. Jumped the lanyard , no help. Swapped out relays and it hasn't missed a beat since.

[BrennanK]

Do yourself a favor and change the $10 relays (get them at an auto parts store).

Where did you get your's and what was the part number?

I just got back from Napa and they wanted $41 for a relay that would fit and was still jacketed.

[rodltg2]

Just order from ski dim.

[Connor]

I just took the old relays out and took them to the auto parts store (A-Line Auto). They are not the exact replacement but that is fine, all you need is for the pins to match and for it to plug in correctly. I am guessing by "jacketed" you mean with the rubber gasket and clicks into place? The relays I purchased do not click in as the originals did but with a little electrical tape they aren't going anywhere...

[Rick]

Many marine parts are sealed or jacketed. This includes almost all electrical components in and around the motor. The alternator, starter, and relays. This is to keep an errant spark out of the bilge. The same goes with marine carburetors. The automotive carb and fuel pump is set up so that if there is a sticky valve or pump the gas overflows onto the ground. In a boat it it set up to flow into the manifold. Needless to say all these things are to keep your boat from becoming a bomb. You can use automotive components in your boat. Just make sure there is no gas vapor or spilled gas the the relay can ignite.