Ready to give up on Johnson

[resteph]

I have a 1985 Johnson 150 Gt. One owner. Problem is it stalls at 2500 rpms. Will not plane out. It starts real easy and idles great. With muffs, it will rev up fine, but under a load it stalls. I soaked and cleaned and rebuilt the carbs, new power packs, new vro pump, new stator, Check compression, all cylinders within 2 lbs, all about 80lbs, Pulled the heads and check the pistons, pistons seem to still have good sharp edges on the domes, and the cylinder walls are good. Replaced with new head gaskets, new intake gasket and carb gasket, new gas lines, new gas filter, checked gas tank vents, new plugs and wires and still will not plane. Sometimes the engine will shut off when put in gear. does not have enough power to load on the trailer. Had to use the crank to load boat on trailer. I have been all summer on this problem. Does anyone have any ideals on what the problem could be or what to look for. Help me, Please

 

[ezeke]

Re: Ready to give up on Johnson

It's a two man job, but if you can borrow an inductive timing light and check each hole while running the boat, you can isolate the cylinders that are dropping out on you. That motor can idle and sound fine on three cylinders with no load.

 

[tashasdaddy]

Re: Ready to give up on Johnson

did you remove and clean all the jets, and their passages, when you did the carbs, blow all out with compressed air? have you checked timing and done a linc n sinc?

 

[seahorse5]

Re: Ready to give up on Johnson

Did you remove and clean the midrange jets that are buried down inside the float bowls as well as the regular idle jets and main jets? There are 6 midrange jets for that motor and most folks not using a service manual while cleaning carbs do not know about them. What did you set the float level and float drop adjustments at?

 

[nymack66]

Re: Ready to give up on Johnson

Lets not give up on anything, Simply use a external fuel tank and test, also use a flashlight and inspect under the flywheel you are looking for a melting brownish stuff if you see any traces please post it , I will tell you how to do trigger and stator test , but external tank first we have to rule fuel out first ..

 

[resteph]

Re: Ready to give up on Johnson

Yes, I did remove and clean all jets and blow clean with compressed air. I have not done a linc and sinc That was going to be my next job for this weekend. Thanks for the reply. I am at my wits end with this engine. It has not give me any trouble since I purchased it in 85

 

[resteph]

Re: Ready to give up on Johnson

try a external tank already, didn't help. Thank for the reply

 

[resteph]

Re: Ready to give up on Johnson

Yes cleaned all the jets, I set the floats level, per manual

 

[resteph]

Re: Ready to give up on Johnson

I will try the inductive timing light . Maybe that will show me if I am dropping a cylinder or two, Thanks

 

[resteph]

Re: Ready to give up on Johnson

Checked under the flywheel when I replaced the stator, everything looked ok. Thanks

 

[nymack66]

Re: Ready to give up on Johnson

So fuel is not an issue, Check under the flywheel, I am thinking a bad stator ! I am out on a limb here but just wanted you to know where I am going with this ..

 

[resteph]

Re: Ready to give up on Johnson

Replaced stator with a new one last month

 

[resteph]

Re: Ready to give up on Johnson

Can the timing base under the stator be a problem and if so, what should I look for

 

[nymack66]

Re: Ready to give up on Johnson

Unfortunately the trigger/timer base does NOT show any sign of failures with the exception of cracks on the inside, Was the stator burnt when you remove it ? If yes chances are the the trigger is shot..

Check the DVA output from the timer base. A reading of at least 0.5V or more from the white wire to the blue, green and purple wires (while connected to the pack) is needed to fire the pack.

 

[resteph]

Re: Ready to give up on Johnson

The stator looked as if it had been hot on one side. I will doo some check on the output from the timer. I am not very good at the electric stuff. I am feeling my way through the electric part of the engine. I am going to try and get help on this part. I will post later what I find. Thanks for all the help and ideals from everyone. You guys are the best help around

 

[nymack66]

Re: Ready to give up on Johnson

I will recommend if you pull the flywheel go ahead and replace the trigger.
Please be sure to post feedback its what I use to rate my knowledge or lack of

 

[LiLGrady17]

Re: Ready to give up on Johnson

Yes, I did remove and clean all jets and blow clean with compressed air.

When I rebuilt my carbs, there was crusty stuff in the small passageways under mycarb's knock out plugs that compressed air wouldn't remove. Single strand copper wire from an old extension cord was needed to completely clear the stuff out..

 

[resteph]

Re: Ready to give up on Johnson

When I rebuilt the carbs, I check all the passage ways and was real careful to make sure that everything in the carbs was clean, Thanks for the post, I am thankful for any suggestions that you guys have to offer.

 

[resteph]

Re: Ready to give up on Johnson

By the term, trigger, Are you talking about the timing base

 

[countvlad]

Re: Ready to give up on Johnson

isnt 80 psi kinda low? i mean i know its all uniform but for my 120 1989 that would be a 1/3 compression loss....