Mercury 60HP Bigfoot issue

bryan428

Recruit
Joined
Jun 13, 2010
Messages
3
My motor is a 1999 mercury 3 cylinder, 2 stroke, 60 HP Bigfoot. I'm having a strange issue with it. When I first start it up and take it out, the boat will run full speed for about 500yards. The boat will then slowly slow down to about half speed and won't go back to full speed until I take it back and let it cool down and take it out later.

I cleaned the carbs and put in new gaskets, new fuel filter, new fuel lines and clamps, new fuel primer bulb and line, everything but a new fuel pump. I spoke with a guy who knows a lot about these engines and he said this motor is very touchy, and has to be jetted richer because of the 10% ethanol gas in the fuel. Would this be causing my issue? Is it a lean condition that is causing me to all of a sudden lose power?

I want to order 3 new jets for the WME carbs, but i'm not sure which size I should get... I also want to replace the fuel pump. I did a compression test on all cylinders and they all read above 115 PSI. Any other suggestions? Thanks!
 

bryan428

Recruit
Joined
Jun 13, 2010
Messages
3
Re: Mercury 60HP Bigfoot issue

I ordered a replacement manual fuel pump and I'm going to drain the ethanol gas and put in regular gas. Anything else I could check?
 

planetech

Cadet
Joined
Jun 6, 2010
Messages
7
Re: Mercury 60HP Bigfoot issue

how's the pee stream? Your water tube could be corrroded shut where it connects under the powerhead if it is strong when you first start it up and it reduces to hardly anything when the thermstat opens. Your thermostat could also be stuck shut not allowing water to cool the engine. If the pee stream stays strong I would check the thermostat.
 
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