Mercury 25hp fuel pump problem

[beaverhound]

I have a 1997 25hp merc tiller. It sat for 3 yrs. i replaced plugs, waterpump, fuel pump diaphram, and completely disasembled the carb and cleaned. i put it all back together and tried to start. i primed the fuel filter and pulled til i was blue. the prime on the carb wont even squirt any fuel. so then i shot a squirt of ether in the carb and opened the throttle manually and gave a pull. fired right up but the minute you let it below say 2000 rpms it stalls. the pump isnt pumping so i even checked the vaccum lines and the plate the carb mounts to for restriction but theyre all clear. i wish i could bypass the pump but on this model the pump is cast to the side of the carb. any suggestions?

 

[groovy.dude]

Re: Mercury 25hp fuel pump problem

Your post is a bit confusing. How are you sure that it is not pumping fuel? I am not familiar with your particular model, but on my smaller engine the first things do it re-check all the gas lines for cracks or leaks. And also I would look at the linkage in the float boawl to make sure that all the measurements are correct. One time while puttting my carb back together I bend the linkage on the float and it cause me some grief. I am no expert by any means!

 

[Starcraftguy1]

Re: Mercury 25hp fuel pump problem

if you are idling at 2000 rpm the pump is pumping.Seems like a carb problem to me.Did you set the floats according to specs?

 

[hamit59]

Re: Mercury 25hp fuel pump problem

I would never spray either into a 2 stroke there is no lube in it. In stead spray premix in it to test.
Will this motor run with out spraying the carbs down?
My first thought was you have a needle valve stuck, or your float level is set wrong.
If your fuel pump is in question tee in a vac gauge. The reading should be 2.5-3 hg
When you cleaned the carb did you soak it? It could be a clogged low speed jet.Not knowing the serial number of your motor. I can't look up the carb they used on it. Try turning out the mix screw to 2 turns to see if will idle.
post back your findings.

 

[robster1213]

Re: Mercury 25hp fuel pump problem

when you say to T into the line. Which line are you T-ing in to? The fuel line? And just check it for vacuum? And that is what the pump is pulling in? I can't think of another one besides the little ones that tap into the transfer ports? But I would think they would read + and - depending on the stroke as they accuate that diaphram..... right?

I am having a similar problem. Mine will start with a prime, but then acts like it's not getting enough fuel. The primer bulb seems to feel ok, and if I squeeze it, it makes no difference. maybe float level or a sticky needle and seat??