Another prop question: 20' MA advice?

[rkarran]

Thanks Sandman! I did the decarb today but haven't tried to see the difference yet. Stiff wind dispersed the smoke pretty good.
I do run non-ethanol fuel and do have Champion plugs. The motor only has 417 hrs. Will take your advice on the leg lube, wp, and t-stat. Thanks much for all that. I gotta find some other props to try, once I benchmark the one I have with speeds and rpms. I know I must turn more at WOT.

[gofastsandman]

http://www.classicseacraft.com/commu...t=prop+testing

The dia. and pitch were all over the place, but I learned a lot of subjective intel.

Thx, BW.
Cheers,
GFS

[rkarran]

Red, my compression is right about 95, across the board. Was told this is a low-compression model by design.
Yes, I'd like to try a 15 x 15.

[gofastsandman]

They made about 11 versions of this motor. Low compression motors will generally last longer. They made 90 commercial motors and 130 bass boat gt`s. They matched the slugs side for side, The key is each bank should be close. 5-10% is considered normal. I`m 87-92 cold, carbs closed. That is a bargaining tool right there.

Cheers,
GFS

[rkarran]

I recorded some numbers this morning. Decarbing the motor did not make any difference to my max rpms.
1500 rpm 5.7mph
2000 rpm 7.7
3000 22.8
3500 27.7
4400wot 34.9

I think I need to try a 15 x 15 prop.