50hp Merc hates cold temps

[Cvivor]

2000, 50hp Merc outboard. Starts right up in all weather conditions. When the temps start dropping like now in New England, the idle increases while at dock, revs to about 2000rpms and won't drop down when engine temp warms up. Linkage is free, carbs perfect. I can see the electric solenoid activate when the engine starts. The rpms start out fine but as engine warms up they increase. Rpms just wont drop.

I do have a specific question, the plastic cam/wheel that rides the black round solenoid, does it ride the top or behind the slotted arm? Mine is riding the top.

Thank you!

 

[jerryjerry05]

Re: 50hp Merc hates cold temps

Sent U a PM

 

[Faztbullet]

Re: 50hp Merc hates cold temps

2 or 4 stroke????

 

[Cvivor]

Re: 50hp Merc hates cold temps

It is a 4 stroke. 2000, 50HP Bigfoot, very low hours. Yesterday it started right up, idle perfect, about 3 minutes later, the engine warmed up and all of a sudden the rpms jumped up to 3000 and stayed there. I watched the linkage,solenoids, nothing moved BUT still the rpms raced when warm. Tryed kicking it down with throttle, nothing helps.

Both solenoids work like they should at cold start and warm. It is driving me crazy.

 

[carholme]

Re: 50hp Merc hates cold temps

This should be the manual for your engine:

http://1manual.com/Mercury manuals/Service Manual PDFs/FourStroke/828631r3/cover.pdf

You must have Adobe Acrobat reader installed to use this manual. If you scroll down to the lower part of the opening page, you will see the various engine components in red. Click on the one you want and when the first page opens, click on the "Save As" icon at the top LH corner of the page and you can save it to your computer.

Parts listing:

http://www.crowleymarine.com/mercury-outboard/1180.cfm

As your problems seem to be happening with the drop in outside air temperature, you may want to check Choke Shutter and Fast Idle adjustments under Carburetor, Pages 3B-17 and 3B-15 respectively.

You will see from the graphs for each adjustment just how OAT sensitive they are.

Gerry

 

[Cvivor]

Re: 50hp Merc hates cold temps

Thanks for the info and service manual link. I will work on it this weekend and post my results.