Motor runs good,then won't start up again

[flatsdude3]

Hey guys, wondering if anyone might have some suggestions.

the motor is a 1978 35hp seahorse, i have gotten it running good but after a short time in the water it turns off and then won't fire again. the motor has good compression, rebuilt the carb, new plugs and coils. Today was the third time i have taken it out and it has stranded me. It ran good for an hour then went to start it and it turns over fine but wouldn't fire. I must be losing either spark or fuel right? Could it be a bad power pack causing the motor to not start again? Any ideas?

 

[5150abf]

Re: Motor runs good,then won't start up again

I have heard of power packs overheating so that could well be it.

I would invest in an OEM manual(not Seloc,Clymers or any CD) available here at iboats, before you throw anymore parts at it, it will tell you exactly what to do and how to test all the different components to see exactly what needs replaced.

 

[Mark_VTfisherman]

Re: Motor runs good,then won't start up again

1] are the plugs wet with gas when this happens?
2] does it start right up when cold?
3] will it stop running on its own or does it run forever and then not start when you have shut it down?

 

[flatsdude3]

Re: Motor runs good,then won't start up again

1) today was the first time i pulled the plugs after it quit firing and they weren't wet at all
2) every time it has quit starting on me i have replaced something (ignition coils, plugs, fuel pump, fuel hoses, carb kit) and mess around with it and get it starting fine. Ran it for an hour in the driveway the other day it ran and started great.
3) The last time the motor just cut off on its own at wide open and wouldn't fire again, today i was idling and running for about 30mins-1hr after the second time i shut it down it would not start again.

Today i noticed that the bulb on the gas line had lost it's prime when it wouldn't start. Tried pumping it and starting at the same time and nothing. Could this possibly be an air leak in the fuel line? I have replaced all the fuel lines

 

[jonesg]

Re: Motor runs good,then won't start up again

When it fails , spark test it with a gap tester, $12 from autozone.

If the spark jumps 7/16th inch then its very likely fuel delivery related.

 

[5150abf]

Re: Motor runs good,then won't start up again

The bulb won't stay hard cause the gas is being pulled by the motor, as soon as you start it it sucks gas out of the bulb and you can get a pump or 2 on it.

As I said, get a manual and find the actual problem, I suppose eventually you will throw the right part at it but that sounds pretty expensive.

 

[tashasdaddy]

Re: Motor runs good,then won't start up again

i agree spark test immediately after it quits, if you loose spark on both plugs, suspect power pack.

 

[flatsdude3]

Re: Motor runs good,then won't start up again

i believe i'm losing spark so i will test it today and see if it is getting spark, before i took it out yesterday it had good bright spark both cylinders. I will replace power pack also, i was planning on replacing all of these things as they are all original and 30 years old.