60HP mariner loosing top end speed

[waiddog]

The motor has always run great, low hours. Took it up in elevation for a fishing trip and now does not run at speeds from before.
This is my cousins boat and trying to help him with it.
My thoughts are when you go from hardly any elevation to 8000 feet air is a lot thinner and maybe the mix should of been adjusted. to rich and has clogged something. Any help would be great.
Thanks
ps. the mech he spoke with stated it has carbon under the rings and needs new rings. I want to call bs on that

 

[carholme]

Re: 60HP mariner loosing top end speed

What is the s/n of the engine?

In the service manual you will find that there is a chart for carburetor jet replacement for higher altitudes. Forget the carbon under the rings problem. You can always clear that out later if it exists with a fuel treatment.


Gerry

 

[achris]

Re: 60HP mariner loosing top end speed

When you say it doesn't run like before. Do you mean when you've come back to near zero elevation, or at 8000'?

Chris......

Yes, carbon under the rings is complete bs.....