How to check fuel system?

[cah412]

I'm working on getting a '77 Merc 110 going and I took off the flywheel, knocked some rust off and I got a decent spark. I gave it a few good pulls and I'm still not getting anywhere. It kinda made a pop type sound that I think was igniting the fuel that was already in the cylinder. After that though, pulling was just for fun and didn't get me anywhere. How do I know that fuel is moving through the system? Should that be the next step once I confirmed I have spark?

 

[cah412]

Re: How to check fuel system?

I appologize for bumping myself but does anyone have any ideas on this? I'd rather not go out buying new parts if I don't know what's wrong but I don't really know where to go next. And my knowledge of small engines is mostly limited to lawnmowers so does this engine work on a suction system for moving fuel or is there a fuel pump hidden somewhere? Thanks.

 

[WillyBWright]

Re: How to check fuel system?

Lood for a brass drain plug at the base of the carb. It'd have a 7/16 hex head if it's there. Remove that and squeeze the primer bulb and see if gas flushes through. The fuel pump is either somewhere between the fuel fitting for the tank and the carb, or is part of the carb on the side. Alternating pulses in the crankcase move a diaphragm that sucks the fuel in one check valve and pushes it out the other.

 

[Shildy]

Re: How to check fuel system?

How do you know if your fuel pump is not working? Would removing the drain bolt in the bottom of the carb and pumping the fuel tell you this?

Thanks

 

[Yepblaze]

Re: How to check fuel system?

I'd try a squirt of premix in the cylinder(s) and see if it fires off on that, as a conformation that the ignition system is working first.

Then if it fires off for a few seconds like that, I'd try priming,choking, and starting.

If that didn't work, I'd pull the carb and and clean it up internally.

Next if that helped and the engine fires off and runs a minute or two then dies, I'd suspect the fuel pump, and look into that.

 

[JB]

Re: How to check fuel system?

Shildey, it is bad manners to hijack someone else's thread.

Start your own thread.