Lost 600 WOT RPM's

[EGallant]

1996 200 HP Johnson J200TXED One of 2 upper main bearings failed. Broken race, no sign of heat or lack of oil, journal on crank A-ok. In time (how long?) broken pieces migrated to #1 cylinder thru lube port. Trashed top of #1 piston and stuck upper ring. This is when I first heard noise in engine. I replaced upper bearing housing assy complete. Honed cylinder, it wasn't to bad, and replaced piston working thru intake manifold. 110 to 115 lbs. compression on all 6 cyls. after repair and about 1 hr. on engine. Now the problem or question. Boat is propped at 6200 RPM with me alone. Normal load, 2 people and gear, 5800RPM. Since the repair I can only get 5600 Max. ?????

 

[Joe Reeves]

Re: Lost 600 WOT RPM's

Normally when a engine cylinder is honed, the engine is completely torn down. This (for one reason) is due to the fact that the crankcase must be thoroughly washed down with soapy water, sprayed clean with a water hose, then all passages blown out with compressed air..... after which all surfaces that could rust are coated with oil.<br /><br />In your case, you honed a cylinder without dismantling the engine completely? if so, it's very unlikely that all of that grit resulting from the honing bars grinding against the steel cylinder could have been trapped and removed.<br /><br />I'd suggest that you tear the engine down completely and do the job properly.

 

[EGallant]

Re: Lost 600 WOT RPM's

Appreciate the quick response and experienced advice on engine teardown. I'm trying to nurse this motor till end of season here in Michigan. Still trying to find lost WOT RPM"s ???

 

[walleyehed]

Re: Lost 600 WOT RPM's

What Joe is saying is the engine is eating itself up by the residual grindings and filings, etc....<br />I don't think you are ever going to see the RPM back where it was with the way you "O/H'd" it.

 

[Joe Reeves]

Re: Lost 600 WOT RPM's

Wallyeyed..... Yep, that's what I was saying.