2001 Honda BF50 low compression - lost HP?

[CaptianJack]

Recently purchased a Shoalwater 16 sport with 2001 Honda BF50. Did a compression check at WOT and got 147, 149, 153. Not the best numbers, but the motor seems to be sound. However it feels under powered.. Any experts out there have a feel how much horsepower I'm getting with those compression numbers?

 

[jgmo]

Those results could indicate any number of things. Yes, there could be a lot of wear. Do you know how many hours are on the outboard?

But other possibilities are incorrect timing due to a slack belt or the belt being off a tooth.

Your valves could need adjusting.

Something we see here on the forum quite often is that it's very common for an outboard to get a lot carbon build up.....probably from a lot of trolling. Time and again I see posts about guys getting low compression readings and, after performing a decarb procedure, the compression improves. Sometimes quite dramatically.

So, while I can't really really give you an accurate percentage of power lost due to the lowered compression, you may be able to bring it up nearer where it ought to be.

One other thing to consider is that the 50 is probably around 1/2 the horsepower your 16' hull is rated for. That could be another reason she feels "sluggish".

 

[chawk_man]

These BF 50's have a reputation for being a very good tough engine. It's hard to wear them out.

If I saw those numbers, I would do a good valve adjustment, replace the belt, reset belt tension to specs, double check the timing, decarb the motor, then readjust the valves again after decarb. Betcha it would get darned close to specs. Don't forget to change the oil after a decarb.

 

[alumarine]

You could also try a different compression gauge.
That's a flat bottom boat? If so, the 50 should be ok'ish.

 

[chawk_man]

Yep - I looked it up - 660 lbs dry weight so a 50 hp in good condition ought to make it get up and go.