motor fires for second then quits

[tjs]

one day motor would fire but shut down immediately. put on lift. next weekend motor fired and ran great. next outing motor ran great shout down in lake. back to original symptom of firing but only run for one second then shut down. switched relays around no change. tested fuel pressure, within tolerance. checked inline fuses and circuit breakers. fuel is full and good. regular use of boat and fuel filters clean. checked safety switch wiring was good and secure. 2000 sport nautique gt-40 touchpad ignition

[gotpwr]

Re: motor fires for second then quits

checked safety switch wiring was good and secure.

If the wiring to the kill switch checks out, my guess is it is something related to the kill switch itself. Try taking the clip off and holding the button out with your finger and see if anything changes. Also, you could bypass the switch completely and see if that has any effect.

[richard]

check this

Check if manifold/riser leaking, will make engine oil milky and wet spark plug, experience one time similar issue.

[tjs]

I bypassed the safety switch and have the same issue. The engine will turn over, fire, rev up for a quick second the automatically shuts down. Also, oil looks good. Thank you for your replies.

[M3Fan]

Be sure the low pressure/high volume fuel pump is working. Even if it makes noise, it could still be messed up. This pump looks like an acorn below the FCC. This is a failure point on the GT40.

[Grant_West]

Dammit I type a long responce to this subject and the website didnt post it.


I have the same problem

My mechanic said to bring a extra spark plug with me and when this happens plug the extra spark plug in the the wire and ground it out and see if the spark keeps going as the motor die's. If the plug keeps sparking as the motor dies its a fuel problem. If the spark dies with the motor its a ignition/electrical problem


I to had hard wired my kill /lanyard switch so I know its not that

He also asked if I can hear the fuel pump turn of when I turn the boat to the start position, He said you should hear the fuel pump circulate.

Also he asked if the boat will keep running if you hold on to the start switch?

Try to see if you can see if the spark go's out with the spark plug trick se if you fuel pump is turning n and try the start button trick. I will report back Please do the same for me

[ag4ever]

Be sure there are no fuel fumes when you test the spark plug trick.

[Mikeski]

The easiest/cheapest thing to do first is replace the two relays shown on page 25, click on the link below and print out page 25:

http://www.planetnautique.com/Correc...e%20Manual.pdf

They are bosch cube relays, one has a shroud that is not necessary for testing purposes.

http://www.partsexpress.com/resources/relays.html

[Mikeski]

This manual is one of the most comprehensive engine diagnostic manuals that I have ever seen. When I had a GT-40 powered boat I kept a printed copy on the shelf. I would highly recommend that anybody with a GT-40 and a reasonable mechanic background keep a printed copy handy.

[Grant_West]

I will replace the stock relay's and keep my fingers crossed that it fixes the problem. Mike what you say for TJS who has replace the relays in his boat and is still having problem's


My mechanic also said that mabey the purple wire that comes off the lanyard and connects to the large circut breaker pannel might be pinched and to check to see if the wire is in good condition all the way to the circut breaker pannel. How does this Purple wire connect to the circut breaker pannel?

[tjs]

thank you for the response and ideas. I will try this afternoon and report back.

[Mikeski]

I am guilty of posting before reading...

Look in that manual, it has great information. I would look first at the throttle servo and/or position sensor then... arghhh, ECM. I would guess that a new ECM might cost $500 or more. I think there are a few testers on e-bay for about $40 right now.

[G-man]

Re: motor fires for second then quits

checked safety switch wiring was good and secure.

If the wiring to the kill switch checks out, my guess is it is something related to the kill switch itself. Try taking the clip off and holding the button out with your finger and see if anything changes. Also, you could bypass the switch completely and see if that has any effect.

I had this happen with my MC. Holding in the button on the kill switch and everything was fine. The clip that holds the lanyard got weak in the middle of the day. The plastic heated up and expanded. I put a sliver of cardboard from my daughters juice box drink between the button and the prong on the lanyard and off we went.

[ag4ever]

RE: Re: motor fires for second then quits

Grant said he has hard wire his kill switch, so that eliminates the cardboard switch.

[Grant_West]

Whell I replaced the relay's at the back of the motor with new ones and my Inttermitin quitting problem surfaced again. Like always it started up and then ran fine after opening the engine compartment. I tryed running the blower to see if this helped and it didnt it quit a few more times over the weekend.

A new symptom poped up. A few times it surgerd like it was running out of gas I threw it in neutral and reved it up like it needed to be cleaned out and it seemed to fix the problem.

Later on the next day the main circut breaker poped. I was under way going 28 mph and the motor just died. I dont know how or why it poped it has never done it before. We reset the circut breaker and that fixed the problem i ran the boat for the next 2 days and it hasent happend again.

Any new idea's Mike said to check my Idle port that it might be dirty?