Johnson 140 won't idle

[thunder]

I have an '83 Johnson 140. Anything below 1200 RPM and it doesn't want to idle. The compression has been checked, it's good. The carbs have been cleaned and rebuilt. My mechanic thinks it could be something in the recirculation system. He says the engine seems to be loading up with fuel at idle, even with it trimmed full out. He replaced the recirc hoses, still ran poor. He has ordered 4 new check valves/filters, but they are not yet installed. Can anyone think of what else it could be? The timing is right on, it has been checked many times. Ant help would be appreciated.

 

[Hooty]

Re: Johnson 140 won't idle

Those recirculating check valves are a good bet. They can be cleaned out with acetone, rubbin' alcohol,etc and a small syringe. <br /><br />c/6<br />Hooty

 

[marinemech]

Re: Johnson 140 won't idle

make sure carbs are properly syncronzized and engine is warming upi agree with "hooty" recirc valves could also be problem and check compression using "bump" method this is the most reliable way to check comp. due to the oil in two stoke cylinders i have had many engines with 110 pounds compression that were badly scored!

 

[thunder]

Re: Johnson 140 won't idle

This powerhead has just completed a total overhaul. I had the cylinders honed by an outboard machinist, new wiseco rings, etc, etc, etc. Unless I really messed up putting it back together, I'm pretty sure the cylinders are in good shape. (At least I pray they're in good shape as I don't want to tear it all down again). Also, I sync'd the carbs according to the Seloc Repair manual, but manuals have been shown to lead me astray in the past. Thanks for your suggestions

 

[thunder]

Re: Johnson 140 won't idle

Just got the bot back from the mechanic, still won't idle. He replaced all four recirc check valves, thing still runs like s**t. It will run for a while at 800 to 900 rpm, below that and it will just stall. After 10 or 15 seconds, it will start to cough and surge from 1100 down to 600. Then ususally it will just stop like someone turned the key off. I have the timing set at four degrees, idling at about 800 rpm. Also, I sprayed starting fluid around the intake cover and the four bypass covers looking for a leak, I didn't find one. Does anyone know anything else I can try? I haven't been able to get this boat in the water yet this year, would like to figure it out before winter. Thanks...

 

[Solittle]

Re: Johnson 140 won't idle

Did you replace the thermostats? Those motors wil not idle very well until they get to normal operating temp.

 

[Dhadley]

Re: Johnson 140 won't idle

Did you just hone the cylinders or were they bored?

 

[thunder]

Re: Johnson 140 won't idle

I replaced both thermostats. Made sure they were installed the right way. The cylinders were only honed, as they had been already bored out to .030 oversize.

 

[kgw]

Re: Johnson 140 won't idle

Thunder,<br />Had the same prob with freinds 120,bad connector pin from stator to power pack

 

[Walker]

Re: Johnson 140 won't idle

What plugs are You using and what are they gapped at.

 

[thunder]

Re: Johnson 140 won't idle

Walker,<br /> I'm running NGK BUHXW-1 plugs, no gap as these are center electrode plugs.

 

[Walker]

Re: Johnson 140 won't idle

Get some Champion L77JC4's and gap them at .030 and give her a try. If it still won't idle, I suggest another carb cleaning session paying particular attention to the idle circuits and them do a proper link and sync.