[SAGENT]

I have a 20' Misty Harbor ponoon with a 2001 Honda BF40 with a 12.125" x 9"
pitch 3 blade prop. At WOT the tach shows about 3900-4000 RPM. The manual for the outboard indicates it should be running anywhere from 5000-6000 RPM. I see on Hondas website the smallest pitch prop for this engine is a 7". The pontoon we had previous to this was a 18' Misty Harbor with a Honda BF25 with a 12" pitch prop that seemed to have similar performance as this one. The BF40 does not start or run very well when cold but seems fine with engine warm. The BF40 has maybe 100 hours on it and new plugs just installed. Anyone have any ideas on where to start?

[zzzzz]

looking through the parts diagrams,it appears you have a manual choke...what is your starting procedure?...as far as the tach goes-you need to check the settings on the back of the tach to make sure it is set correctly then look for a prop problem

[steelespike]

Assuming the engine is sound and throttle opening fully I think I would start by raising the motor vertically.I saw a specs on a 50 etec on a 23 ft toon running a 13 3/4 X13 prop turning 5,375 at 19.5 mph.
I would think your 40 on a 20 should approach 5,000 with a 9in prop.
Something is amiss hopefully just the setup.