Honda Engine Woes
I've got a 2006 Honda BF50 ( A4 Carbed Generation ) on the back of my rib. Recently it's been causing me some headaches with intermittent rough and lumpy running and I was wondering if anyone could share some knowledge with me.
Symptoms In A Normal Day Of Running:
•The engine takes a good bit of cranking to he going in the morning but once it's started it seems to idle ok.
•Leaving the marina in the morning the engine runs just fine, idling nice and smoothly.
•Upon acceleration out of the marina there is a bit of reluctancy/bogging down as I throttle up to get on the plane, and there is a good bit of vibration/roughness until I'm going at speed.
•Once the boat is on the plane the engine runs really sweetly, above about 2,200rpm throttle response is great and the engine is very smooth. Even in the highest reaches of the rev range the engine doesn't miss a beat.
•However, when bringing the boat back down to idle / general pottering about speed after being thrashed for a bit it runs rough as a dog, idling very slowly (around 400rpm rather than the usual 800-900rpm). The engine will stall frequently when idling/going between gears and can be a real pain to get going again.
•If i try to get the boat on the plane again the engine is very reluctant to accelerate, sounding very rough and vibrating a lot. But once I've reached about 2,200rpm everything is fine, and as before, responsiveness and smoothness return at higher revs.
•The boat will continue to run rough for the rest of the day at slow speeds.
•Another peculiar thing I've noticed is that when the engine is running rough and I raise the warm up lever, the revs are all over the place. If I raise the lever about half way, the revs can vary erratically between 1200rpm and 2,500rpm.
I know it's quite a long description but hopefully someone could maybe shed some light on what might be up. The engine is serviced regularly and has always been run on premium fuel from new so I don't think it's anything I've done to the boat.
Any help that could be offered would be greatly appreciated.
Cheers Guys, Alex.