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75 HP Stinger is a stinker

B

Biggizmo

New member
Ahoy...and thanx ahead of time to read and offer help.

I have a 1978 Johnson 75 HP Stinger.
Starts and runs great...out of water.
Using muffs..runs and idles like an old Hamilton Service Watch.
Gear linkage disconnected...in tank..nice throttle up.
Link and synch proceedure...new gas. Seafoam. New plugs...cleaned carbs.
Compression is between 120 and 128 between 1st and 3rd cylinders.
No fuel puking but heavy consumption.
On the water...starts...idles...warms up....put it in gear...throttle up and it stutters and dies.
Any help would be graciously appreciated.
 
Check fuel pump diaphragm.----Running " great " on a hose means nothing.----It will " bark and roar " on 2 of the 3 cylinders
 
Carb had a piece of deteriorated fuel line debris.
Got it running and she flew.
Tool it out twice and got her up to 40+ MPH...
Today I took her out. Started right up.
Warmed it up while I parked truck and trailer.
Took it out to open water gave it throttle...only had half throttle.
Pumped bulb while in full throttle that seemed to clear it up.
Eased off throttle after about 4 minutes and just cruised at about 25MPH.
It started increasing throttle on its own.
So I backed off a bit...it surged a few times then had a steady run...
I throttled up to circle and go back to where I wanted to do some fishing.
Then it made a strange noise and just stopped dead in the water.
It started up for about 3 seconds then died again.
I tried to start it and it acted like dead battery. Would hardly crank.
I waited for about 10 minutes.
Cranked it over and it acted like it wanted to start...fired
and made about 20 revolutions
Then died again.
Motor turns freely by hand. Rather tight though.
Compression on all cylinders are still at 120 +...
I must add that about 2.5 gallons of fuel had been
consumed during this run.
Any ideas what I am missing?
 
Quote edited...............

Biggizmo said:
Carb had a piece of deteriorated fuel line debris.
Got it running and she flew.
Took it out to open water gave it throttle...only had half throttle.
Pumped bulb while in full throttle that seemed to clear it up.
Then it made a strange noise and just stopped dead in the water.
I tried to start it and it acted like dead battery. Would hardly crank.
I waited for about 10 minutes.
Cranked it over and it acted like it wanted to start...fired and made about 20 revolutions Then died again.
Motor turns freely by hand. Rather tight though.
Compression on all cylinders are still at 120 +...
Click to expand...

Priming fuel bulb to clear up power problem. = Indicates lack of fuel.
Strange noise? Stopped dead? = Uh-oh! Something came loose.
Flywheel turns tight? = Powerhead or lower unit failure.

First thing to do is to remove the lower unit to determine which unit failed... the powerhead or the lower unit.

Is this engine new to you or have you owned it for some time? Are you using a 50/1 mixture?

With the key ON (engine NOT running... ground out the overheat sensor wire that leads out of the cylinder head (TAN wire). The warning horn should sound steady when that wire is grounded. Does it?
 
Turns out...it was needing carb rebuild and powerpack.
All new fuel system...plugs...seals...
Tank...everything...practically rebuilt engine.
120+ psi...no need to go there. Never fix what ain't broke.
No...I haven't owned this very long.
Bought it last summer ...14 ft JetSter...motor
and EZ LOADER all for a small cost....$180
I now have over $600 into it...but it runs like new.
 
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