25hp 05

[toonin22]

I got a 2005 25hp mercury that has been
overheated the compression checks fine I replaced impeller and had to replace cylinder cover gasket and had cover fixed was warped replaced exhaust manifold gaskets and cleaned Carb three times I got a Carb kit new gas and plugs. The engine runs for 20 30 seconds then dies no clue what the problem could be please help I am.stumped

 

[carholme]

Re: 25hp 05

What is your engine s/n?

Try to start it again and when it starts to die, keep pumping the bulb and see if it keeps running. If so, you know you will have to re-build the fuel pump.

Gerry

 

[toonin22]

Re: 25hp 05

The fuel pump is part of the carburator

 

[carholme]

Re: 25hp 05

Well, I can see why you are stumped. You don't RTFQ.

I asked for the s/n as you didn't mention if it was a 2/4 stroke.

However, with that illuminating answer which you have provided, I see that it is a two stroke and I don't care if the fuel pump is screwed to the oars, if it keeps running by squeezing the bulb, you are going to have to re-build the fuel pump.

But I leave it to you to figure it out.

Gerry

 

[ande0652]

Re: 25hp 05

I had the same problem on a motor I bought. It would only run if I kept squeezing the bulb. I checked the and rebuilt the fuel pump and had the same problem. I knew the pump wasn't working but it was all new. After a lot of headscratching, I finally found that the new gasket that went between the carbuerator and head was missing a critical hole. Compare your old gasket to your new one or look at the back of your carb and see if the gasket is covering a large rectangular hole.

 

[toonin22]

Re: 25hp 05

Hey thanks checked out all the new parts and compared them to the old ones and sure enough the gasket that seals the carb to block is different put the old one back on and the engine is running fine. Thanks for your help.