1079 70HP Johnson cold starts but stuggles with warm starts

[jeffkbga]

Hello,

I'm new to being a boat owner and recently purchased a boat that has a 1979 70HP Johnson Sea Horse Motor. When I get it to the launch I pump the bulb, raise the idle, push the key button in, and it starts with ease. I will turn the motor off for a period of time when I get to my fishing spot but when I go to start it again, it only starts 50% of the time. I have tried alot of combinations regarding start techniques between idle speed, pumping the bulb, not bumping the bulb, choke, no choke etc... I have ran Sea Foam through it and bought new plugs. I haven't put the new plugs in yet as I'm waiting to get SeaFoam through it first. I have replaced the fuel line and bulb. I will be replacing plugs before I take it out again. In a nutshell, after it has been sitting for days or weeks, it starts with ease. When running, it runs like a dream. After it has been off for and hour or so, it has a 50/50 chance of starting. I did find that when it doesn't want to start, after it has been running and then turned off for a few hours, I simply need to turn the key WHILE pumping the bulb 2-3 times and then it starts. Any suggestions?

Thanks!

 

[tashasdaddy]

Re: 1079 70HP Johnson cold starts but stuggles with warm starts

could be a sticking float needle, that is flooding the motor after it runs. try disconnecting fuel line, when it won't start, now try starting several time to get rid of excess fuel, after it starts reconnect fuel line.

 

[jeffkbga]

Re: 1079 70HP Johnson cold starts but stuggles with warm starts

Thanks for the reply. I will definately try that. My initial thought was that it was flooding. However, I ruled that out when I found that all i need to do is pump the valve at the same time as turning the key when it's acting up. Then is starts. It works everytime when I do it, smokes for about 5 seconds, and then is fine. Basically, when I force gas into it while i'm turning the key, it starts. I will try your advice. If it is the needle in the float, is there anything I can do short of taking carbs out? Thanks again, I appreciate your help!

 

[Boatonbrain]

Re: 1079 70HP Johnson cold starts but stuggles with warm starts

As an aside, taking the carbs out and inspecting/cleaning them is not that bad. I pulled mine out of my Evinrude 50 hp last year and found it rather empowering to finally do it. It will also give you an idea of whether things are gummed up.