86 Johnson V4 120hp

[kgilly22]

New to boating and recently purchased a Ranger Commanche with Johnson V4
120hp. Took it out for the first time yesterday and noticed it struggled to stay running while idleing. Ran perfectly at higher speeds but had a hard time in the no wake zones. The motor would turnover and start but not run very long before dieing. Any suggestions?

 

[tashasdaddy]

Re: 86 Johnson V4 120hp

possibly clogged low speed jets, or the idle speed screw need to be adjusted.

 

[DUKE1]

Re: 86 Johnson V4 120hp

I had a 86 Johnson V4 140hp Looper and it was a sneezy engine at idle..although it usually stayed running. Like yours, mine would just hum at speed but didn't like idle much. I'm sure someone with more technical knowledge than I will chime in...but I don't think they were ever known for being wonderful at low speed....loopers love to run. I always use SEAFOAM treatment in all my fill ups. This might be one more thing to keep those carbs clean.

Good Luck,
Duke1

 

[kgilly22]

Re: 86 Johnson V4 120hp

Thanks for the advice. Another thing I noticed was that i could not get the primer bulb firm. I checked the fuel lines and noticed one of the clamps was broke off and the line was very cracked and weathered near where it entered the motor casing. Could this have an effect on idleing?

 

[DUKE1]

Re: 86 Johnson V4 120hp

Through osmosis and reading this site...I think if your fuel primer bulb won't stay firm you might want to check your fuel tank and make sure it can vent, as this can cause a vacuum effect. They also say that the bulb itself should be changed from time to time as they can wear out.

D1

 

[ezeke]

Re: 86 Johnson V4 120hp

Check that cracked connection again and all of the fuel system. Any air entering the system will cause uneven running of the engine, and can cause the engine to run lean with potentially serious damage.

The loopers need to have the recirculation check valves working properly, but do a thorough de-carbon treatment first or they will just clog up again. http://forums.iboats.com/showthread.php?t=158076