vibrating Honda 15hp 4 stroke

[Dale Wickenheiser]

Hi,<br />we have a 1999 Honda 4 stroke BF 15 A that until recently ran great.<br />The other day while using it, it suddenly started vibrating and I noticed a loss of pushing power. I had put it in idle to talk with one of my crews and when I started up again I noticed the remote control vibrating and the loss of power. <br />It starts immediately, idles fine and seems to rev normally. One person suggested replacing the prop and another said the timing was off. I didn't notice that I had hit anything before it started to vibrate. When I checked the prop it didn't seem to be bent, a little dull, but it was always like that.<br />I don't know much about timing but would think that if it was off, it wouldn't start so easily. <br /> <br />I'm looking for some feedback before I pull it and drop it off with a shop or spend the money for timing equipment or a new prop. <br /><br />Thanks.

 

[gss036]

Re: vibrating Honda 15hp 4 stroke

Sounds like you lost one cylinder and it will run rough on just one cylinder. I don't think the timing would change that fast. You would be able to see a ding in the prop to make a vibratition. Replace the spark plugs before you anything, one might have gone bad. I have a 15hp myself and have never had a problem with it.

 

[vikingham]

Re: vibrating Honda 15hp 4 stroke

I agree with Gary that the engine is probably running on one cylinder when revved.<br /><br />Your problem sounds a lot like my situation with a '98 Honda 90, which has turned out to be a stuck carburetor float- the needle valve never closes, so gas keeps flowing into the engine whether it needs it or not. It seems like a number of others have had the same problem (the mechanic who's supposed to clean all my carbs this week said it's pretty common).<br /><br />In addition to the rough running, mine had several other symptoms: smell of gasoline during/after operation; unburned gas coming out the exhaust when the fast idle lever is raised while tied at the dock; gooey black spark plug in affected cylinder; gas would flow out of the affected carb when (with the engine SHUT OFF AND FULLY COOL!) I pumped the fuel line priming bulb to pressurize the fuel lines. <br /><br />It could, of course, be something else entirely - swapping out your plugs is easy, cheap, and harmless, and if that fixes it, great. You could also try checking your fuel filters to see if there's crud in your gas supply. But if you do have the stuck carb problem, you should tend to it pronto - gas leaks are nothing to mess with. I'm hoping that a carb teardown and cleaning will do the trick.