74 johnson 70hp will not stay running in lake

[newtowater]

Engine fires up immediately in back yard with muffs on and stays running untill either I turn key off or if I push throttle lever all the way down. It will always start back up quickly. The bottom carb throttle lever has a little bit of play to it and mechanic told me it will have a rough idle. When I put it in the water though, it will only idle for a few minutes at a time, will shut off immediately after attempting to put in gear and will only stay idling as long as I hit the choke toggle every 30-45 seconds. Has new plugs and just had carbs cleaned. Any ideas would be helpful. Thanks.

 

[newtowater]

Re: 74 johnson 70hp

Re: 74 johnson 70hp

Just wondering if I have offended anyone or am I just not asking the question correctly?

 

[fishon13]

Re: 74 johnson 70hp

Re: 74 johnson 70hp

Pretty straight forward question I'm sure you didn't offend anyone, awesome people here. Just keep your question on the front page and one of the many much more knowledgable salty dogs will get to your problem BTY welcome aboard

 

[newtowater]

Re: 74 johnson 70hp

Re: 74 johnson 70hp

Thanks. Any advice would be helpful at this point.

 

[Boss Hawg]

Re: 74 johnson 70hp

Re: 74 johnson 70hp

You stated the carbs were cleaned - does that mean taken off, dismantled & really cleaned? A rebuild might be needed -
Compression checked-
Spark checked-
Can you get it going while in water to any kind of speed ?
These guys are great & will certianly help but you need to give them all the info you can
I had somewhat the same problem on my '87 70hp & with help & advice here she be now a runner
Good luck & a bump up

 

[newtowater]

Re: 74 johnson 70hp

Re: 74 johnson 70hp

According to the mech that I took it to right after I bought the boat, he did rebuild the carbs and flushed the fuel lines. 140-150 psi in all three and good spark. It was after he put them on that he mentioned that the shaft on the bottom carb was worn and would cause a rough idle but should be fine once in gear on the water. It has a new tank of fuel and will start up with muffs on in the back yard with no problem and will stay running as long as I dont lower the warm up lever all the way down. I also noticed that I can put it in gear with muffs on but when I put it back in nuetral, I have to slightly raise the warm up lever or it will shut off. But apparently with the addded pressure of the exhaust in the water, I cant lower the lever at all without it shutting off or for that matter put it in gear without it shutting off. When it is running it sounds good and has no discernible miss to it even if I "goose it" to wot in the backyard for a few seconds.Hope this added info helps!!

 

[newtowater]

Re: 74 johnson 70hp

Re: 74 johnson 70hp

bump

 

[newtowater]

Re: 74 johnson 70hp will not stay running in lake

^^^^^bump

 

[newtowater]

Re: 74 johnson 70hp will not stay running in lake

bump again

 

[tlynch99]

Re: 74 johnson 70hp will not stay running in lake

I had a similar problem, and did a link and sync as stated in my manual and the helped out quite a bit. Now mine acts a little like yours does, untill I run it over 25% throttle for a few minutes, then it will idle fine, as most as it's now warmed up. I wonder about the raising of the warm up lever, allowing it to stay running at idle. I wonder if it is a timing issue?