Joker, these are deep V hulls, which means there is a lot of planing surface on the water which means resistance...IMO they need a large diameter prop to get all the push against that resistance...I used a 15 1/4" x 17 for that reason and was completely satisfied that my motor was getting all the prefomance possible on that hull...The only reason I didn't use a 15 1/2" diameter was that it was a little too heavy and caused a rattle in the lower unit, but your motor should handle it...you didn't mention SS or alum...use SS for best performance...hope this helps you find the right prop...sometimes it's not easy...

]

I don't know too much, but maybe you should run some seafoam through it to clean out the cylinders/plugs. However the fact that one plug is fouling may mean that cylinder is not firing and the unused oil is causing the residue.

the prop on there is a 15- 1/2 X 15 aluminum. She really jumps onto plane, since I had it repitched I can get 5000 on Tach ( if Tach is correct ) but doesn't feel that powerfull only 30 mph. on GPS. Last year I got 30 mph at 4000 RPM. I will do a compression test on all cylinders, if that is good I will research if doing a seafoam treatment that everyone talks about on this forum will be safe to do to my engine. maybe that is all it needs.

I have a 1995 150 HP Ocean Pro. Is the seafoam safe to do on this engine ? I only have ten hours running double oil ( break in ) that was last year. This year about 4 - 5 hours on motor, that doesn't seem like a lot, should I have to do a treatment already ? By the way my marina is a 20 minute in and out no wake zone, so I am going very slow a lot, could that be reason for some extra fouling of plugs ?

Actually, I think that I'd try a 14 1/2 x 17 prop for that engine. (The smaller dia. will let your RPM's come up a little, and the extra pitch should help with your top end once they get there). As to the fouling, is it really fouling, (as in not firing) or does it just have some black residue on it from the break-in? I use Seafoam as a preventitive measure, not as a corrective. And even then I only use it about every 6 tankfuls or so. (When I remember to add it) :head:

My Honda spun up to redline (6gs) as fast as you could ask it to w/both the 15 1/4 & 15 1/2 props...the extra diameter didn't slow it a bit...

As for the suspicion of idling causing the cyls to load up...it may very well be...a trick to prevent that at idle is to TILT the motor UP a little PAST LEVEL...that prevents unburned oil from building up in the top of the cyl and fouling the plug...a marine tech told me that years ago and it worked on the 150 Evinrude I had at the time...

Joker, I reread some stuff and edited a portion I posted earlier about a 17" stainless or a 19" aluminum should be about right. It was supposed to be a 17" stainless or 15" aluminum.
I ran a 14.8x17 aluminum and a 14x19 stainless on mine and got almost the same exact numbers fuel, speed and rpm wise. I need to go to a 17" stainless.
http://www.wellcraftv20.com/communit...ad.php?t=12543

And get you a gallon of Seafoam, mix to what they suggest. Think it's 1oz per gallon.