1987 Johnson 120 low rpm issue and smoke at startup

[jpinheiro33]

Ok i have two issues with my motor i am wondering anyone can help me with.

First and most important is about half the time i use my engine at low rpms (under 1000) it seems to cut off a cylinder maybe two when i give it a little juice (most of the time) it will go to about 1500 rpms and the problem goes away runs great at wot no hesitation lots of power and then when i go back down to idle the problem will come back, warm or cold this happens. Any ideas???


Next the motor seems to smoke a whole lot right at startup, everytime i start it, maybe a little more after the first time i start it each day. Maybe this is the same problem for both maybe two different problems. Thanks for any input!!!!

 

[kenmyfam]

Re: 1987 Johnson 120 low rpm issue and smoke at startup

Compression check, spark check, carb re-build and link and sync sound in order to begin with.

 

[kenmyfam]

Re: 1987 Johnson 120 low rpm issue and smoke at startup

Forgot about the smoking question.
Most of them are smokier at start up from cold or after being off for a spell. If it is always smokey then that is a different matter.

 

[jpinheiro33]

Re: 1987 Johnson 120 low rpm issue and smoke at startup

Ok now how would i go aboout doing a link and sync????

 

[kenmyfam]

Re: 1987 Johnson 120 low rpm issue and smoke at startup

Ok now how would i go aboout doing a link and sync????

Start with a good manual (OEM) and read the "Top Secret Files" at the top of page 1.

 

[jpinheiro33]

Re: 1987 Johnson 120 low rpm issue and smoke at startup

Also, i dont know if this pertains to that, but do you, or anyone for that matter, know what the timing advance is supposed to be set at??????

 

[kenmyfam]

Re: 1987 Johnson 120 low rpm issue and smoke at startup

That's where the OEM manual comes in to play. You will have all the info on hand. Someone out here I am certain will know the answer to your question but a good manual is good reading even when your motor is running well.

 

[jpinheiro33]

Re: 1987 Johnson 120 low rpm issue and smoke at startup

I Hear ya! I will have to do that when my marina opens. thanks for the input!

 

[ezeke]

Re: 1987 Johnson 120 low rpm issue and smoke at startup

If you have a lot of smoke every time you start, warm or cold, you are burning off excess unburned oil.

The following items can influence the amount of oil left after running:

Any restriction on the gasoline side of a working VRO/OMS pump will cause the pump to add more oil than needed;

Any air leak on the gasoline side of the VRO/OMS will cause the working VRO/OMS pump to add more oil than needed and will cause rough idlle and can potentially damage the engine from running lean;

Failure to follow BRP/Evinrude Maintenance schedule in re: de-carbon treatment will cause the engine to build up carbon;

Failure to maintain the recirculation check valves will result in excess oil being left in the engine;

Failure to store the motor in the running postion so that it can drain properly after use will result in more oil being left in the engine;

Failure to maintain the thermostats and assure that the engine is running at the correct temperature will result in excess unburned oil and excess carbon and plug fouling;

Running the motor over-propped will cause lugging the engine which leads to coking; and,

The quality of the oil being used will also influence the amount of smoke being generated. Look for high flashpoint and try different oils; this is one place where being cheap does not make sense.

BTW, the boneyards are full of motors that had their timing messed up by people who had no idea what they were doing. It is best to leave that to the trained mechanic with the proper tools.

 

[jpinheiro33]

Re: 1987 Johnson 120 low rpm issue and smoke at startup

My motor was switched over to 50:1 mixure and the vro side of the pump was eliminated ok now im going to need to do some serious tuning and checks. Thanks for the info!!!

 

[jpinheiro33]

Re: 1987 Johnson 120 low rpm issue and smoke at startup

oh and i use johnson xd30, definitely not cheap but maybe the older motors dont like the new stuff. anyone had any experience with that???