boatmon345
Petty Officer 2nd Class
- Joined
- Apr 26, 2006
- Messages
- 113
Rebuilding 1997 Yamaha 150HP 2 stroke Salt Water Series II S150TXRV powerhead.<br />( Click here to view updated blog with new pictures )<br /><br />I have all my parts, and this Saturday expect to rebuild the powerhead and get as far as I can.<br /><br />Problem I have is that for the last 2 weeks I have been concerned that I may have made a big mistake spraying Rustoleum primer inside all of the water passages including inside the V of the block, associated water passages, as well as cylinder heads (water side), and water jackets.<br /><br />Now let me preface this by saying that several local powerhead rebuilders say they do this to slow corrosion, and they have told me not to worry about the concerns that I am about to describe, except for one individual. So I felt better about this situation, but still am unsettled.<br /><br />Specifically, the concerns I have are:<br />1) The Rustoleum I used is rust color and called Rusty Metal Primer. Somehow I missed where it states on the can not to use on surfaces that exceed 200 degrees F AFTER I applied the paint (don't laugh). The reason I chose this product was because of it's claim of "superior adhesion". I am concerned that some of my water contacting surfaces of the powerhead will get hotter than that (esp. around the cylinders), which may cause the paint to lift and subsequently possibly block water passages leading to an overheat situation, or worse, engine failure.<br />( Rustoleum Rusty Metal Primer Information )<br /><br />2) In some areas, specifically in between the V of the block where I could not reach down with the can, I have applied several fairly thick coatings of this Rustoleum. I am concerned that this thick coating may act as a significant insulator as far as the block being able to transfer heat to the water, causing the engine to run significantly hotter than it was designed to, causing eventual failure.<br /><br />3) I contacted Rustoleum and they advised that they have no product designed to coat the inside of an engine AND DO NOT APPLY RUSTOLEUM TO THE INSIDE OF MY ENGINE bla bla bla (I suppose the conservative response is to avoid liability).<br /> They also stated that Rusty Metal Primer is for steel, not aluminum as my block is aluminum. UGGGG.<br /><br />SO, I decided to perform a test:<br />I sprayed the same Rustoleum on the exhaust pipe of my car about halfway down the length of the car. I drove around for a day, and in the evening the paint was still there (Rodbolt, stop laughing).<br />And although not perfectly simulated, I ran the car and was down on the ground spraying water at the hot painted surface of the pipe trying to see if I could get the paint to crack or peel off. It didn't. The water sizzled away until the pipe cooled enough for the water not to sizzle.<br /><br />However, obviously this test only covered a couple of heat-cool cycles. Not hundreds of cycles as I expect to put my powerhead through.<br /><br />I have considered putting the powerhead back together as is, and after running for the break-in period, pulling the flywheel and the top water cavity cover to look in and view the condition of the paint.<br /><br />Engine has and will continue to be run in saltwater.<br /><br />Stripping this paint off I think may be next to impossible, but I could be wrong.<br /><br />SO I ask you this:<br />I would like to hear from all powerhead rebuilders what you know about painting of the waterpassage surfaces (please) and what you think about my situation. <br /><br />Thank you very much. I got to put this concern to bed.
.<br /><br />thanks