Engine Rattle at high speed - Honda 50

[Johnv]

I have a 1999 Honda 4 stroke 50 which starts, idles and operates fine up to 4500 RPM. Once it exceeds this RPM it starts to develop a rattle sound which gets progressively louder as RPM increases. It does not make this sound while the engine is still cold but once it gets warm the rattle occurs at this speed. Could this be timing, fuel octane ???<br /><br />Any ideas or suggestions as to cause would be welcome; thanks.

 

[MajBach]

Re: Engine Rattle at high speed - Honda 50

it's so hard to guess at sounds hen you cant actually hear them. any chance this is your hood vibrating or did you already consider that?<br />Other things that come to mind are: pinging - low octane(doubtful), valve slap from incorrect valve adjustment(again doubtful since you would likely hear this at low rpms moreso than at high but it does match the engine temperature symptoms). Did it just start sounding like this all of a sudden or was it gradual that this sound came on and it has worsened?

 

[Johnv]

Re: Engine Rattle at high speed - Honda 50

I have run it with hood off and sound persists so not likely loose hood. Also have tried mid grade fuel with no luck. The sound has gotten a little more noticeable since last season. Not sure whether to describe the sound as "rattle" or "light knock". <br /><br />Thanks for any additional ideas.

 

[MajBach]

Re: Engine Rattle at high speed - Honda 50

Kinda off topic, but where are you from specifcally in Ontario?<br />BTW, I think it's your valves.

 

[Johnv]

Re: Engine Rattle at high speed - Honda 50

Home in Etobicoke, cottage north of Huntsville.<br /><br />Any sense of costs of adjusting valves?

 

[Skinnywater]

Re: Engine Rattle at high speed - Honda 50

Don't stop with the valve adjustment. Have the timing belt adjusted at the same time.<br /><br />I cured a low speed rattle recently on mine by greaseing the splines of the driveshaft.<br /><br />In any event, keep us informed please.<br /><br />"Any sense of costs of adjusting valves?"<br />This must be Canadian language for: Any idea how much it costs to adjust valves? <br />The whole job, along with a belt adjustment shouldn't take anymore then 40-70 minutes.

 

[MajBach]

Re: Engine Rattle at high speed - Honda 50

I think Bravo Marine in Midland qutoed me $150. Mine needs to be done too.<br />Where do you typically have yours serviced? I 've never gone to the cove in Barrie but they seem fairly good.<br /><br />First outing this year was Lake of Bays. Caught a few lakers but that type of fishing isn't rally my favourite.

 

[Johnv]

Re: Engine Rattle at high speed - Honda 50

I am not familiar with dealers in Barrie or Midland. Have had some work done at Mainland Marine in Etobicoke but boat is now up north. <br /><br />My fishing is mainly for smallmouth at Doe Lake for now.<br /><br />Thanks for help so far. Any other suggestions would be appreciated.

 

[Johnv]

Re: Engine Rattle at high speed - Honda 50

Reply to Majbach<br /><br />Saw your reply to Ron1 re the Canadian Honda Rep. Could you provide name and phone number?<br /><br />thanks<br /><br />john

 

[MajBach]

Re: Engine Rattle at high speed - Honda 50

Before I made that post, I looked for that info but couldn't find it. Decided to look again and I did indeed locate it this time. I hope posting this doesn't come back to bite me in the *** ; it might have been confidential when he gave it to me..LOL<br />his name is Ken Parherst - really nice guy - 1-888-946-6329. Works out of Scarborough I think. I didn't find him, he found me. I went through my records and discovered I e-mailed honda marine via the internet and he responded to me via telephone.<br />Good Luck