Timing

[Joker2]

sounds complicated, maybe I'll just leave it. I am getting 4200 RPM's max running a 15-1/2 X 15 Alum. prop recently repitched for more RPM. Yesterday I got 29mph @ 4200, 2 adults 4 small children, 35 Gall. fuel, new plugs. Feels to slow based on numbers I have seen on this site. tried compression check to see if I got all 6 cyl. firing all the way, comp. tested wasn't holdng, I'll get another one. Also hearing what other people are running sounds like the 15" prop should be a 14-1/2 X 17 or 19. Any thoughts

[Destroyer]

Originally Posted by Joker2

sounds complicated, maybe I'll just leave it. I am getting 4200 RPM's max running a 15-1/2 X 15 Alum. prop recently repitched for more RPM. Yesterday I got 29mph @ 4200, 2 adults 4 small children, 35 Gall. fuel, new plugs. Feels to slow based on numbers I have seen on this site. tried compression check to see if I got all 6 cyl. firing all the way, comp. tested wasn't holdng, I'll get another one. Also hearing what other people are running sounds like the 15" prop should be a 14-1/2 X 17 or 19. Any thoughts

The only question I have is when they repitched the prop, what did they repitch it to? It almost sounds like you're running too much prop. I think before I did anything else I'd take a different prop with a pitch that I knew was accurate (wasn't screwed with) and see what my results were with it... As you know from my other post here I think that a 14 1/2 is plenty of diameter for your engine. And I'd think that a 15 or a 17 will be about the right pitch for general overall performance.

[Joker2]

Thanks , I would like to do that but the prop house won't lend me one to trial , I have to buy it first

[Destroyer]

Originally Posted by Joker2

Thanks , I would like to do that but the prop house won't lend me one to trial , I have to buy it first

(Sounds like it's time to find a new prop house ) Unfortunately, the only spare prop I have for OMC is a 13 1/4 x 17 that I carry as my "get home" prop if the one on my engine becomes damaged. Call Docks Marina in Budd Lake, NJ. He's got a room full (really, an entire room) of used props. Maybe you can work something out with him.