Honda BF8A - doesn't want to rev up to top rpm

[stephennicholls531]

I've just spent the winter rebuilding this particular long leg outboard - new rings, valve job, the whole shootin' match. It starts and idles great, but when out on the lake, it doesn't seem to be able to get to a decent top rpm. The Honda can only push my 16' Lund to 10 MPH, but a Yamaha 8 2-stroke I rebuilt last year easily managed 15 MPH.

One thing I can think of is that it's trying to swing a prop that's too big. What is the diameter of an original equipment prop supposed to be? The one I have - that came with it when I salvaged the motor - is about 9.5 inches...and there are no numbers on it.

The other might be that - because it's a long leg, the prop is too deep, and there's just too much drag.

Any ideas?

 

[langer]

Re: Honda BF8A - doesn't want to rev up to top rpm

i'm having a similar problem, i got this motor from a garage sale for
$185 cleaned it up and it actually runs pretty good, i use it as a kicker motor on a 18 foot sled, i don't think that the prop is low enough below the bottom of the boat... for some reason it cavitates when it starts to pick up speed, but the anti cavitation plate is well below the water... wierd. huh...
if you get good advise sail it my way...or i'll just read the posts.
jonah

 

[Bolt49]

Re: Honda BF8A - doesn't want to rev up to top rpm

Hi, having the same problem with BF20, did you guys ever figure this out?

 

[JUSTINTIME]

Re: Honda BF8A - doesn't want to rev up to top rpm

Hi, having the same problem with BF20, did you guys ever figure this out?

start a new thread