Engine died at full throttle?

[bmen123]

I have a 20hp 200model. I was running full throttle, in gear when the motor suddenly lost power like it came out of gear. The motor then stalled like it was under heavy load. I was able to restart, but as soon as I put it in gear it would stall the motor. Any suggestions on where I should start looking for the problem?

thanks,
still paddling....​

 

[JB]

Re: Engine died at full throttle?

You may have blown her up. Start with a compression check.

 

[bmen123]

Re: Engine died at full throttle?

would the engine still start and run if the engine is cooked? I never tried running it at an idle for more than a few seconds before putting it in gear. It was after I put it in gear that it would seem to be under load and stall.

 

[JB]

Re: Engine died at full throttle?

You have a dead cylinder. Do the compression check.

 

[bmen123]

Re: Engine died at full throttle?

I have checked the compression and both cylinders are just over 120. What is a normal range for this motor?

 

[JB]

Re: Engine died at full throttle?

Compression is fine. PSI matters little as long as it is over 50-60psi. What matters is that they are within 10% of each other.

I assume (with all the risks attending) that you have only one carb on that engine, so your problem is probably either ignition or scavenging related.

First, let's confirm my dead cylinder theory. Fire her up and disable each spark plug, in turn. If killing a cylinder that way does not cause a drop in idle speed that cylinder is not making power (dead).

If both cylinders are making power I suspect that your geartrain is trying to sieze, and that's where my qualification to offer more advice would end.

Let us know what you find.