| Author |
Message |
    
levent
New member
Username: levs
Post Number: 1
Registered: 10-2009
| | Posted on Monday, October 05, 2009 - 02:43 am: | 
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I have a honda 50hp,it idles & runs to mid throttle smooth as. On full throttle there is a rattle in the motor,kind of sounds like loose tappets.would anyone know if they are adjustable & what the specified adjustment is.There"s still a chance it could be bottom end bearings,if so is it a common problem with this model. Im a transmission mechanic by trade,outboards are a passion for me but im no expert on them. Any positive info would be much apriciated.}}} |
Bob Vialle
Member
Username: bobmech
Post Number: 37
Registered: 07-2008
| | Posted on Monday, October 05, 2009 - 03:27 pm: |
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It is most likely the engine is "pinging" due to old/stale fuel. If this continues you may damage the pistons.
Use fresh fuel & retest, & recommend a fuel stabiliser to prevent further problems.
Bob |
mike
Advanced Member
Username: hondadude
Post Number: 174
Registered: 03-2009
| | Posted on Monday, October 05, 2009 - 09:09 pm: |
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Valve clearances are adjustable. I would recommend purchasing a Manual and follow the procedure step by step.
You did not say how old the motor was...
Have you had someone try the locate the sound more accurately by using a short hose to the ear and moving it around the engine?
Check your gearlube and oil. These engines are tricky when it comes to locating strange sounds. Could it be coming from your lower unit?
If the sound is more of a whine, you may want to pull the flywheel and check the magnets. They sometimes delaminate in the older motors and start hitting the coils under the flywheel. You will see real fast if it is by the metal fragments or the scoring on the coils. I have just recently had one come in on a no crank situation, because it was locked up under the flywheel due to the delamination.
The flywheel is easy to get off (4 bolts) however, check a manual on how to put it back on. It requires certain surfaces to be lubricated and the bolts properly torqued.
Happy hunting! |
levent
New member
Username: levs
Post Number: 2
Registered: 10-2009
| | Posted on Tuesday, October 06, 2009 - 04:16 am: |
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You know what Bob,i did'nt even think of the engine "pinging".Ive had the same fuel in the tank for atleast 5 months.Being a 60L tank 3/4's full,it's hard not to use it.In that amount of time would it couse pinging. |
levent
New member
Username: levs
Post Number: 3
Registered: 10-2009
| | Posted on Tuesday, October 06, 2009 - 04:31 am: |
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Sorry about that Mike, it's a 99'model honda. The rattle is comming from inside the cowling. It is a "rattle" not a whine. |
Bob Vialle
Member
Username: bobmech
Post Number: 38
Registered: 07-2008
| | Posted on Tuesday, October 06, 2009 - 06:36 pm: |
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In that amount of time(5 mths) if you're not using a fuel stabiliser the fuel will certainly cause the engine to "ping" under load.
If low octane fuel is stored for more than approx 1 month you must treat it with a fuel stabiliser additive to prevent it from going stale.
If high octane fuel is stored it must be treated within approx 2 months.
Mike has raised a good point regarding the flywheel magnets delaminating. This problem will sound like a whine or noisy tappet but will be there at high & low RPM, whereas "pinging" will only sound at higher RPM & under load, which is what you have described.
Although sounds are sometimes difficult to diagnose in a forum, I believe the fuel is the problem.
Let us know how you get on.
Bob |
