1977 Johnson 35 Seahorse starting issues

[yeos]

1977 Johnson 35hp Seahorse 35EL77C

I've had this motor for over a month now and I have been having an issue starting it up. I should re-phrase it, I am having an issue re-starting it after it has been running. From a cold start it starts just fine. No excessive cranking needed to get it started and idling. The issue here is that after it has been started, warmed up, shut down, and left off for a few minutes it will not start back up. If I try to start it it will just crank with no sign of wanting to start.

I prime the bulb and it gets hard and still won't start.

Fuel tank is properly venting (no signs of it getting sucked into itself).

Plugs are new and have been swapped out and still the same issue.

No fuel leaks.

Water pump kit I just changed out water flows nicely when the motor is running.

Battery is new.


If I try to start it back up right after shutting it off it will start up fine. It has to sit for quite a while before it will want to start again. When started it will run with no issues. I'm new to outboards (handy with automobile engines) so let me know if I have overlooked anything.

 

[Daviet]

Re: 1977 Johnson 35 Seahorse starting issues

Have you checked the spark when it woun't start?
Look in the carb throat and see if any fuel is puddling in there, maybe time to overhaul the carb.

 

[yeos]

Re: 1977 Johnson 35 Seahorse starting issues

No I have not checked for spark when it won't start. I will try that tomorrow. My boat is a 15ft runabout and I have the fuel tank in the bow. The bulb is 1.5' from the fuel tank and the remaining ~11' run back to the motor. This wouldn't be an issue would it?


Is this the carb throat you speak of?




Here's a picture of the plug condition

 

[Daviet]

Re: 1977 Johnson 35 Seahorse starting issues

As long as the tank is not a lot lower than the engine you should be OK.
Yes, that is the carb throat I was talking about.
What are the numbers on the plug?

 

[yeos]

Re: 1977 Johnson 35 Seahorse starting issues

I would say that the tank is mounted no more than 12" lower than the motor. Plugs are Champion QL77JC4 gapped at 0.030. One maintenance item I have not changed out is the thermostat. Could that be a possible culprit?

 

[Daviet]

Re: 1977 Johnson 35 Seahorse starting issues

I doubt the thermostat would cause your problem, the engine isn't overheating is it?
I would check the carb and see if it was flooding when shut off.
Make sure the spark is there when it woun't start.

 

[yeos]

Re: 1977 Johnson 35 Seahorse starting issues

Are there any obvious signs that it is overheating? Steady water is coming from the pee hole and the two exhaust holes at the rear spits out water as well.

 

[yeos]

Re: 1977 Johnson 35 Seahorse starting issues

I'll tell you what. A new tank of gas plus stabil marine treatment and I have yet to replicate the starting issue. I'm crossing my fingers that this is fixed! However thanks for the assistance Daviet.

 

[Daviet]

Re: 1977 Johnson 35 Seahorse starting issues

I hope you found your problem.

 

[yeos]

Re: 1977 Johnson 35 Seahorse starting issues

Put the boat in the water today. Started right up and ran great. Cruised the lake for an hour before shutting it down at a fishing spot. Fished for an hour and when I tried to start the motor back up I ran into the same starting issue. I was able to start it back up after 20 mins of intermittent cranking and pumping the fuel bulb. I will do the spark diagnostic sometime this week.