Pics of scratches on my crank case / rotary face

[Chips]

I have a few scratches / grooves on the face of my rotary part on the case of my engine. I wanted to see if you guys think these grooves are deep enough to cause my engine not to rev under a load...

Also, I can slightly move my flywheel back and forth without the rotary shaft moving. So there is some play. Is that normal?

 

[El Toro 33809]

Any idea of what caused the scratches? Has it been running? Something may have dropped into the intake and destroyed the brass gear on the rotary valve shaft. That would cause the play you are referring to.

 

[Chips]

Not sure what caused it. It was that way when I bought it unfortunately. It had been running, and sorta still does.... It runs and sounds fine on land, but wont rev out on the water under a load.

So there should be no play whatsoever when turning the flywheel and the rotary shaft? If that's the case, what part are you referring to that might be damaged? Thanks!

 

[El Toro 33809]

Have you run a compression test on the engine? I don't think there should be any play. The part I am speaking of is on the shaft that the rotary valve turns on. You can see it in the upper left of the second photo. Inside the engine on that shaft is a brass gear that turns from the center of the crank. If something jammed the plate and kept it from spinning, the gear could be stripped. Chances are it would not run at all then since the intake timing would be off.

 

[Chips]

It has always had around 125-135 PSI for compression, before and after I replaced the rotary cover that was worn. I did just find out that my timing was off by about 20 degrees. Its hard to be totally accurate with the slop in the shaft but it sounds MUCH better. I am heading to the lake now to see if it actually runs on the water. I will report back with results!

 

[El Toro 33809]

Sounds like you found the issue. Good luck on the lake.

 

[Dr Honda]

improper timing can show up as a drop in compression.

The scratch is deep... but I've see worse. You should be fine.

 

[Chips]

Well I just got back from the lake, and hallelujah...it runs and runs well! This is the first time the boat has run well and not had cavitation issues. I am so happy. Finally, after so many trips back and forth to the lake and all the help here from you all on this forum - I have a running boat. :thumbsup: