82 Johnson back fired and stopped.

[KevinS1970]

I started my 1982 15hp Johnson motor, gave it full throttle (showing out for my son) and then I heard a backfire and the motor stopped running. I tried starting again, and the cord wouldn't turn the flywheel. I manually turned the flywheel counter clockwise several turns and then pulled the cord the flywheel is turning. But still wouldn't crank. I sprayed started fluid in spark plug hole and tried to crank. it would only backfire..The plugs are firing.. im guessing perhaps the motor jumped timing???? Do anyone have any idea what I should do before a repair man? lol.. Thanks in advance.

 

[racerone]

A 2 hp or a 235 hp motor ?------But pull the flywheel off to check the key that positions it for the timing.

 

[KevinS1970]

sorry, but its a 15hp 1982..Thanks

 

[racerone]

Are you going to check for a bad flywheel key ?

 

[KevinS1970]

yes...however, I have to get a puller to get started...I really could use a service manual..Ive checked everywhere for 1 online but only come up with purchasing one.. any better solutions??

 

[KevinS1970]

If Im pulling the starter rope after spraying starter fluid in the spark plug hole, and it backfires doesn't that eliminate the flywheel key?

 

[Bosunsmate]

If Im pulling the starter rope after spraying starter fluid in the spark plug hole, and it backfires doesn't that eliminate the flywheel key?

nope, definitely not, it suggests it actually.
Move the flywheel to 0deg and check top cylinder is at top dead centre and that will save you buying a flywheel puller (unless you do actually need to get it off as the key is shown to be busted by this prior test)

 

[KevinS1970]

OK, THANKS, I will get this done and let you guys know what I found.

 

[jimmbo]

Starting Fluid proves nothing as it ignites from compression, not spark. It can also do a far bit of damage to a two stroke,

In the original post, you say you gave it full throttle, Was this in gear, on a boat, in a lake or river? Or was it on a garden hose or in a test tank?

 

[KevinS1970]

On a garden hose (in gear)

 

[jimmbo]

Inspect the block carefully for a hole from a connecting rod

 

[Silvertip]

You learned that you cannot (or should not) rev an engine without a load on it. Sort of like putting a brick on the gas pedal on your car while it is in neutral or park and then going in the house for a soda. Bad things happen, they happen quickly, and parts that are inside the engine tend to find their way outside the engine.

 

[KevinS1970]

Yep i figured that out. I only had it rev up for maybe 2 - 3 seconds before it backfired. However, looking back at it, i scratched my head and said, "how stupid was that!" Its very depressing because i spent over 800 on this project. I bought all the parts for remote steering to match that motor and never had a chance to put it on the water........sucks.

 

[w2much]

Only 800. BOAT

 

[Bosunsmate]

Yep i figured that out. I only had it rev up for maybe 2 - 3 seconds before it backfired. However, looking back at it, i scratched my head and said, "how stupid was that!" Its very depressing because i spent over 800 on this project. I bought all the parts for remote steering to match that motor and never had a chance to put it on the water........sucks.

Dont write it off until you have actually checked it over and if needs be replacing one piston will take a newbie about three/four hours work and about $100 and it can be done while sitting in a nice spot so keep at it

 

[boobie]

Read post # 7 again and do it !!