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BF25 not running past 2500 rpm's under load...what am i missing?

S

s4rhoolie

New member
We installed 1997 BF25 long shaft on my father in law's pontoon, motor starts and idles fine, in neutral revs in higher rpm range (5000 +) and once shifted forward, when full throttle applied - gets to 2500rpm's and stays there. It runs smooth. Some repairman suggested that prop might be spun but it was checked and no signs of that. Prop have 10 pitch. All cables are adjusted nicely, no free play and no loose cables anywhere. Can't figure it out, it feels like its running in a limp mode but can't tell. We are using controls from BF50 Honda, hope that's not an issue. When ignition switch is turned ON alarm/buzzer does not sound, not sure if it's even working. Fresh water pump and thermostat, water stream coming out from the motor is strong and cool. Motor does not have hydraulic tilt/trim, 3 wires coming out of control box are not plugged (loose) Carbs are cleaned few weeks ago, if there is anything else that might be clogged or dirty - please let me know. Did not check plugs...Any suggestion is welcome and appreciated, need to resolve this asap and there is no Honda tech anywhere close by. Thx
 
First thing to do is to be sure that the carburetors are fully open at full throttle.

Next, make sure that all cylinders are firing. Pull spark plug wires off one at a time and make sure that the engine rpms go down each time one is removed.

Make sure you are using NGK spark plugs - DR7EA.

Make sure that your tachometer is set at the correct setting. Your rpm's may be higher than the 2500 that you are reading. If you are using the tach that was used with a 50 HP Honda, it may not have any settings to change on the back and it is not compatible with the 25 HP.

The alarm and buzzer does not sound when turning the key on and starting this engine. That only occurs with fuel injected engines.

Lastly, if the prop hub was spun, the rpms would shoot up high. You have too big of a prop on it. As a comparison, a 60 HP Honda uses a 9 pitch prop on most pontoons. The smallest pitch that Honda sells for this motor is 10 x 8 1/4. That is probably closer to what you need.

There.....a few things to check.


Mike
 
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