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heavyduty 83 90hp johnson two stroke v-4 stalls

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heavyduty

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recent rebuild starts good runs on plain good then just stops just like i turned it off then restarts fine and away we go again after short time on plain at near full speed it shuts down again 1983 johnson J90TLCTE v'4 two stroke rebuilt carbs and fuel pump last week
 
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noticed battery weak on restart would weak battery cause shutdown iam using extra battery on restart after starting i unhook extra battery may also have charging issues
 
Not sure what makes your motor to be a " heavy duty model "-----Is it a commercial model ?--------The ignition system runs itself via the flywheel magneto and it does not need the 12 volt battery to generate the spark.-----------------Look for problems in the wiring harness / ignition switch and or the kill switch.
 
racerone said:
Not sure what makes your motor to be a " heavy duty model "-----Is it a commercial model ?--------The ignition system runs itself via the flywheel magneto and it does not need the 12 volt battery to generate the spark.-----------------Look for problems in the wiring harness / ignition switch and or the kill switch.
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sorry bought H/D prefix ,put my name in wrong spot ,engine regular 90hp johnson J90TLCTE
 
Is this what is happening?

Run full throttle, engine just shuts down. Restarts, but acts like battery is weak when re-starting. Seems to run OK, but then after short time at full throttle, shuts down again.
Is that it?

If, so, you have a cylinder running lean, and causing the piston to swell up and seize from the heat generated. When you go to restart, the engine has cooled slightly, but may still be tight.

The damage is done. If you pull the heads, you will see that one or more cylinders are scored.

Rebuild time, or just correct the lean running cylinder, and run it.
I have done exactly that, and the engine ran fine for years.


EDIT: Re-read your first post....sounds like it is lean seizing. It COULD be that the rebuilder got it too tight when machining.
 
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daselbee said:
Is this what is happening?

Run full throttle, engine just shuts down. Restarts, but acts like battery is weak when re-starting. Seems to run OK, but then after short time at full throttle, shuts down again.
Is that it?

If, so, you have a cylinder running lean, and causing the piston to swell up and seize from the heat generated. When you go to restart, the engine has cooled slightly, but may still be tight.

The damage is done. If you pull the heads, you will see that one or more cylinders are scored.

Rebuild time, or just correct the lean running cylinder, and run it.
I have done exactly that, and the engine ran fine for years.


EDIT: Re-read your first post....sounds like it is lean seizing. It COULD be that the rebuilder got it too tight when machining.
Click to expand...

sounds very posable how can i correct lean cyl??
 
Well, first thing to do is a compression check. If it indeed has done this WOT partial seizing, one or more of the cyls will be scored. Maybe not much, but surely scored.
I would do the compression test, then pull the head on the related low compression cylinder. Verify scored walls.

If you have all four scoring, I would lean toward the engine being built too tight.
If you only have one, it too could be tight, but I would look at all aspects of the carb/intake system on that cylinder. Look for clogged HS jet, look for air leaks at the gaskets, look for restricted fuel flow to that cyl (kinked fuel line), also a possibility is the condition of the water deflectors.

All this should have been checked at the time of the rebuild tho.

If fuel delivery is OK, then maybe time to take it back to the rebuilder to check the tightness of the assembly.

You should be able to grab the top of the piston and wiggle it around in the cylinder. I know, it sounds strange, but there is enough play to wiggle them
Maybe three wiggle good, and the scored one doesn't wiggle....something like that.

Good luck to you. It sounds like maybe a rebuild gone bad though, to me.

I hope you have 125 all around, and it is not as I fear.
 
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