Re: running hot
A number of years ago while on vacation, my father burned out the impeller on my boat (he ran it for about 5 minutes at idle on the trailer to warm it up while I was in the bathroom). Anyway, the marina had one available (off brand...can't remember the name) so I bought it and sat in the parking lot for about 3 hours replacing it.
I dropped her in the water and shoved off. The boat would start to overheat whenever the rpms went over 3000, but would cool right down as soon as I got off the throttle.
Puzzled, that evening I pulled the boat back out and tore it down again to check my work. I'd changed the impeller plenty of times before (I change it every year) and I know what I'm doing. Everything I did was perfect.
I put it all back together and launched the next day. Exact same problem.
At this point I started thinking about the impeller itself. It seemed exactly the same, but I was guessing it wasn't.
I went to another marina and picked up a merc impeller that day. Pulled the old one out. Put them side-by-side, on top of each other, etc. Everything was exactly the same...except....the first one was made form a VERY soft rubber compound and offered no resistance when squished.
I put the merc impeller in, no further problems.
Just a tidbit related to this question I thought might be helpful to someone down the shore. Be careful what you buy!
Chuck
