merc 25hp 2 stoke

[Wilsonriverfisher]

Took boat out today its spring!!! It ran fin about 5 miles upriver but then was hard to start and and only 1/4 horsepower if that at WOT. Checked the bulb it was hard as a rock. Stopped and checked the filter and it looked ok blew it out and shook the gas can. It started to give me 100 percent for ahile but hesitated at times. At low throttle it actually made a ping a loud one but not at Wot..Any help would be great...I am planning on changing the dirty old sparkplugs, filter and using some heat on the gas in case I have water in there from sitting all winter..and doing using some carb cleaner..What do you think

 

[Yepblaze]

Re: merc 25hp 2 stoke

It could be the carb plugging up or the ignition system giving you problems.

Personally, I'd start by taking off the carb and clearing it of any debris, checking to see that clean fuel is actually getting to it, and probably a fresh set of plugs because they are cheap and easy.

If all that went OK and I was secure in knowing I had addressed them in a sound fashion I might start looking into ignition components.

Mercury made a whole lot of different models of 25hp motors so this advice is pretty much generic outboard motor stuff.

While you are at it check the compression to alleviate that from any concerns.

 

[OldMercsRule]

Re: merc 25hp 2 stoke

My early 1980s 25 hp Merc ran on one then two cylinders then back to one when the switch box laid down on me.

As Yepblaze said: #1 check the conrpression, and at the same time check the spark (on both cylinders).

Make sure the fuel system is tight and free from water, before ya yank the carb off.

BTW the fuel pump is intrigal with the carb on that model.

Good luck. JR

 

[Wilsonriverfisher]

Re: merc 25hp 2 stoke

Thanks guys its a 1996 mercury 25hp.. I bought it used from a real anal fishermen who took good care of it..The plugs are worn down! It was used some last summer and put away for winter with nothing done to it..I also left the vent on the gas can open and then filled it up saturday.. Is there a water seperator on my model?

 

[Yepblaze]

Re: merc 25hp 2 stoke

I had one with the integral pump and the fuel line just before it entered the carb would press up against a sharp metal edge and wear a hole in itself. It would suck air, and cause a lack of fuel to the carb, and consequenty fuel pump. It would leak when pressurized by the primer bulb. So it was easy to spot.

It did it a couple times till I moved the fitting angle slightly.

 

[Wilsonriverfisher]

Re: merc 25hp 2 stoke

new plugs and a little carb cleaner shot in the motor is running top notch....

Thanks guys