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1999 Merc 200 Flywheel Turns but won't Crank

P

Phan000

New member
Motor ran fine for three days. It stalled while in idle.
When I tried to immediatly restart it would'nt cranks.

Now when I try to start it the flywheel spins, but nothing happens.

What should I check first?

Thanks for your help.
 
What should I check first?
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The "man overboard lanyard kill switch"...it may have tripped. If it is working then check for spark at each plug wire w/a spark tester set at 7/16". It needs to be a blue loud snapping spark. Pull the spark plugs and look at the electrode ceramic. It should be brown. Check cylinder compression w/the plugs out and kill switch tripped to stop the ignition. Check for fuel mix getting to the cylinders. Spray a good 2-3 second blast of WD-40 or spray Seafoam into the carb throats and crank it to see if it fires. If it does then the fuel is not getting to the cylinders.
 
guyjg said:
The "man overboard lanyard kill switch"...it may have tripped. If it is working then check for spark at each plug wire w/a spark tester set at 7/16". It needs to be a blue loud snapping spark. Pull the spark plugs and look at the electrode ceramic. It should be brown. Check cylinder compression w/the plugs out and kill switch tripped to stop the ignition. Check for fuel mix getting to the cylinders. Spray a good 2-3 second blast of WD-40 or spray Seafoam into the carb throats and crank it to see if it fires. If it does then the fuel is not getting to the cylinders.
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The motor has spark, good battery and the plugs are wet. I sprayed fuel in the carbs and got it to sputter for a minute but she still won't run.

it smokes a bunch and will only run really rought for a minute at w.o.t.

could this be a fuel carb issue? I just had them cleans and rebuilt a few months back.
 
I sprayed fuel in the carbs and got it to sputter for a minute but she still won't run.
Click to expand...
How old is the fuel? Does the fuel squeeze bulb get firm? Check the fuel filter on the engine. If the fuel pump quit the engine will still run untill the carbs are dry.

You need 3 things: fuel, compression and spark...miss just 1 and it won't start. It was running good and just quit so something is missing. Is the spark blue, loud and snapping and will it jump a 7/16" gap? Check it w/a spark board so you can see all of the plugs sparking side by side for comparison. Get one from an autoparts store or make one. Check compression...100+ PSI is good.
 
The fuel is a mix, but mostly fresh. I looked at the spark again and it is strong on each cylinder.

I noticed some debris in the bowl of the filter, so I replaced. The motor started right up and ran much better.

it still will not idle at all and needs 1/4 throttle or it stalls out.

Does this sound like bad fuel, and or another carb issue?

Thanks for all the help! This board is a great source of information.
 
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