Johnson 9.9 issues..

[kpresley84]

hi, i have a '77 johnson 9.9...it idles ok, but when you give it gas to get up to speed it just bogs down and runs a low rpms...i checked the plugs and the top one was clean and the bottom one was fouled out...does that make any sense?? I was told it could be a power pack...i was thinking carburator issues but it appears one one plug is getting good spark...any help would be greatly appreciated..Thanks...Kenny.. P.S. im new on here and not very knowledgeable about boat motors..

 

[mikesea]

Re: Johnson 9.9 issues..

did the problem just develop,or has the eng been sitting for a while,if sitting,i say your carb has gotten dirty and will need to be taken apart ,soaked in cleaner you can buy carb cleaner to spray all the chemical from soaking off,there are minute passages inside that become plugged by debris not seen by eye,resulting in poor fuel delivery.if you have spark to both cyl.your pack is fine,if just one cyl has spark,it likely would be the coil,you can swap the coils to check if one is bad,it is very important all electrical connections including ground wires arent corroded or rusty,make sure the spark plug wires arent rusty inside and not cut by the hatch cover mechanism

 

[kpresley84]

Re: Johnson 9.9 issues..

thanks mikesea, i just got the motor from a buddy that said if i fix it i can have it so thats what i'm doing...i have checked both coils...one of them gets more spark that the other...like i said before..one plug is clean and the other is fouled out...thats what is throwing me for a loop..will a new power pack give a stronger spark? i'll keep working on it and yall feed me some info...thanks. kenny

 

[CATransplant]

Re: Johnson 9.9 issues..

Did it run any better after you put new plugs in it? Have you checked compression on both cylinders?

 

[kpresley84]

Re: Johnson 9.9 issues..

still the same after new plugs and both cylinders have good compression..i'm going to try a power pack and see what that does and go from there...

 

[Kflc]

Re: Johnson 9.9 issues..

Also, if you have one poor spark, the power pack is still ok but you have a weak coil, fix that first as the motor may not be firing because of it.