I have a 1996 carbed 75 Honda. It looks new and I keep it as good as I can. Did have an issue with ethanol last year and had carbs rebuilt, tank pumped clean and now use regular gas and run a 10 micron filter. The motor was running the best it ever has......until today. Was out on the river when she idled down on her own, ran rough and almost stalled. My first thought was fuel because of the previous issue. Had wife hold onto dock while I unscrewed filter and emptied into container. Fuel looked clear and fine. Was able to get started and headed back to dock. Got her up on plane but at wide open throttle would only do 24mph [normally 50]. Once in a while she would surge to wide open and run fine for a few seconds then cut back down again. I could tell she was running rough like on 3 cylinders instead of 4.
Back home I first checked the plugs. There was one that was not snapped on tight but did not make any difference in running when I snapped it in fully. I pulled all plugs and they looked fine. I then pulled one at a time with engine running. For some reason the bottom plug caused engine to stall when others did not. Not sure why.
Then I drained each carb into a glass jar thinking some crap got into carbs from the line between filtyer and engine. All fuel was clear. There was one strange thing. I started at the bottom carb and worked up. When I got to the top carb there was no fuel to drain. I don't ever remember that happening before. Is it possible one of the fuel pumps is to blame? It looks like one [there are 2] pump handles 2 carbs. Would appreciate any suggestions from those with a pay grade higher than mine before it goes to the shop.
Back home I first checked the plugs. There was one that was not snapped on tight but did not make any difference in running when I snapped it in fully. I pulled all plugs and they looked fine. I then pulled one at a time with engine running. For some reason the bottom plug caused engine to stall when others did not. Not sure why.
Then I drained each carb into a glass jar thinking some crap got into carbs from the line between filtyer and engine. All fuel was clear. There was one strange thing. I started at the bottom carb and worked up. When I got to the top carb there was no fuel to drain. I don't ever remember that happening before. Is it possible one of the fuel pumps is to blame? It looks like one [there are 2] pump handles 2 carbs. Would appreciate any suggestions from those with a pay grade higher than mine before it goes to the shop.