Alum in prop (long)

[topcat46]

1999 225 OX66....Tried out a new prop even though wind gusts were 25 MPH...On returning checked for carbon in the prop and found a thin film of aluminum (?) fanning out off two prop posts..So, here is what has been done. Checked compression (indicator stream was spitting) and all were close. This was done with low engine temp due to short heat cycle because of the spitting. Changed poppet, water pump and checked thermos. Test run on hose showed good indicator stream and head temp of starboard: top to bottom of 104-105 degrees; port side reached 155 and I shut it down. Installed new port thermo and ran (hose) for 25 minutes with starboard: same temps and port: top 126- middle 127- bottom 128....Temp of indicator stream was cold and exhaust was lukewarm.....Oh yea, from the bottom the tuner looked fine and could see no further signs of aluminum.
Do I take it to the shop and have block pulled to check for damage or go fishing? What say you?

[99yam40]

found a thin film of aluminum (?) fanning out off two prop posts..

I am not sure what this means
Did you find some melted metal stuck to prop?
and what are prop posts?

[robert graham]

I'm not sure I understand your question or perceived problem. Maybe clean the prop area, then run the motor down the lake and back to check for further/new deposits of aluminum? Could the aluminum? be some metallic anti-seize compound coming from prop splines or driveshaft splines or bushing area? Good Luck!

[boats.net]

I'm not sure what you mean either, you said checked compression but didn't say if any were low, did you see any alum on spark plugs?

[topcat46]

OK...My wife doesn't understand me either... The prop simply has a thin film of alum in two places on the inside....A few specs can be seen behind the prop and in the exhaust area.....There was no alum on the plugs.....Compression was 80 on all cylinders except one was 85 (on a warm not hot engine)....The old water pump had taken a set and should have already been replaced...

My questions are: (1)Why is there such a difference in head temps? (2)Could this be from molten alum? (3) Based on experience, with the chances of destroying the lower unit, what should be done? Run it or take to the shop ($1000 to pull & check)?

[jb123]

DOUBT melted alum would make it all the way down to the prop
you DO need to service your cooling system tho...
new stats, PRV and pump/housing

[CatCam]

Are you sure it isn't some type of Anti-Sieze that was used when your prop was mounted?? Maybe it is an Aluminum-Graphite Anti-Seize paste.....
Probably Vibra-TITE 907A.......Look it up!!

[99yam40]

OK...My wife doesn't understand me either... The prop simply has a thin film of alum in two places on the inside....A few specs can be seen behind the prop and in the exhaust area.....There was no alum on the plugs.....Compression was 80 on all cylinders except one was 85 (on a warm not hot engine)....The old water pump had taken a set and should have already been replaced...

My questions are: (1)Why is there such a difference in head temps? (2)Could this be from molten alum? (3) Based on experience, with the chances of destroying the lower unit, what should be done? Run it or take to the shop ($1000 to pull & check)?

80 psi sounds kind of low may check again and maybe have a different compression gauge handy to see if it agrees.

How did you check the stats? maybe they are opening at different temps or you have some blockage in some of the cooling passages.

Could you be asking about the exhaust tuner not getting the cooling needed and overheating the lower unit/prop due to too hot of exhaust?
Seems like I have read about that happening and causing the rubber hubs in props to go out due to overheating, but never heard of that destroying lower unit.

[topcat46]

Again, sorry for my lousy communication skills..99yam40 initially the concern was for a melted tuner,however, the head temps threw me a curve....The stats were checked suspended w/thermo in pan of water. One did have some corrosion and that was the culprit I suppose. Anyway, the motor now has new stats, water pump and poppet valve. I took Robert's advice and gave it a good workout today with no new "shiny stuff" appearing on the prop or exhaust.
Thanks to each of you for responding to a confusing post and have a Happy Thanksgiving.
Tom