HONDA 50 MISFIRE - HELP ME!!!

[normantibbles]

HELP, I have a Honda 50HP. Last time I took it out it ran on 2 cylinders under 2000 rpm. Over then it went fine up to 40mph on a 4.5m Rib. Checked, valves, balanced carbs, mixture and put on 3 new plug caps as they were arcing internally. Also 3 new plugs. Just went for a cruise down the Thames (London) and ran fine at 1800 rpm for about 30 mins. It then just went onto 2 cylinders (Squeesed fuel bulb-no difference). Pulled up, had an Ice cream whilst looking over the motor, pulled caps off etc. Started again and it then ran fine for about an hour. On return home checked plugs, bottom 2 black, top one completely as new. Was the top cylinder not firing and was the plug cleaned by the fuel? Anyone any ideas what to check next - I am running out of ideas. Could it be a coil that is breaking down when hot. HELP

 

[DJ]

Re: HONDA 50 MISFIRE - HELP ME!!!

A "clean" plug is quite often a sign of water ingestion.<br /><br />Also, that carburetor for that cylinder may be fouled.

 

[hondon]

Re: HONDA 50 MISFIRE - HELP ME!!!

Are you utilizing a water separating fuel filter?Take a fuel sample from the quick connect at the engine into a safe container,then tell us what you see .Be carefull,no smoking please.

 

[normantibbles]

Re: HONDA 50 MISFIRE - HELP ME!!!

Thanks for your replies - the tank is new and I can't see how water has got in. The filter is OK and I drained it off. I think its more electrical than a fuel problem. The carb has been stripped and cleaned.

 

[kenwitt]

Re: HONDA 50 MISFIRE - HELP ME!!!

I have a BF 50 [Test for spark] I am firing on one cylinder only.. Have FSM... ignition is a very complex issue... most [ all? ]ignition/electrical componets are not returnable..<br /><br />I know how to use a VOM which will check almost all of these componets..I'm taking to the dealer.. why .. probaly need special tools..<br />[flywheel lock and puller]<br /><br />Wasted a lot of time with the standard fuel/carb.<br />stuff.. notice my call for answers on ignition question..wisely has zero replies..<br /><br />no spark = ignition problem!!!!!! ken

 

[cp]

Re: HONDA 50 MISFIRE - HELP ME!!!

ukribman - A simple test to see if you have spark is to pull off the plug wires one at a time with the engine running. If you get no change when pulling a given plug wire, then it's likely that plug was not firing to begin with (or that cylinder wasn't getting fuel, but you say the carbs are clean, synchronized, etc.). For example, if you pull the top plug wire and the engine dies (or runs noticeably rougher), that plug had been firing. If you then pull the middle wire and nothing happens, that plug was likely doing nothing to begin with. In this example you'd then backtrack on the middle plug to see why it wasn't firing. At least you'll know you're looking for something electrical. Good luck.

 

[normantibbles]

Re: HONDA 50 MISFIRE - HELP ME!!!

Thanks PCHONDA, <br /><br />Spoke to HONDA at the boat show - they seem to think its a CDI fault. Couldn't pull the caps off one at a time, as when at home was running fine!<br />Seen a 45hp powerhead for sale, may just get that and put all the electrical components on, not sure what the difference between a 45 and 50 is, may just be smaller carbs.<br /><br />Thanks for your reply.