bertsmobile1
Lawn Royalty
- Joined
- Nov 29, 2014
- Threads
- 65
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- 24,995
I did an overhaul on the carb tonight. I had a spare matching carb body that I knew was in good shape so I cleaned it again and swapped it out. I put in another new diaphragm and both gaskets. I replaced the fuel lines. I started it up and again it ran strong at first but quickly started to choke out. When I pointed it up in the air it would run good again. So based on that I'm confident this is not a carb issue.
I'm guessing now that perhaps the rubber grommet that the fuel lines pass though is not sealing well. When I tilt the blower up the grommet is submerged in fuel and that's when it runs smooth. When I lower it the grommet is exposed to air inside the tank. I haven's seen any fuel leaking from the grommet but I can't imagine what else it could be. I have replaced that once before. It's a three hose grommet with the third hose going to what I guess is an air check valve. I'm going to replace that and see what happens. It looks in good shape though.
Side note...when I was cleaning out this second carb body I blew out the small screen on the flip side of the needle valve. I was going to replace it with a spare I had but I forgot. If I leave it out am I asking for trouble or would it be alright to run it without it. I've pulled that carb apart about a dozen times now and I'd really like to avoid doing it again if possible. I'm pretty cautious about clean fuel and I've never seen a dirty screen in any of my equipment. I was going to leave it and if the carb fouled up because of it I would just pull it off and clean it then, hopefully a long time from now. Am I crazy for even thinking that?
You bet you Charlie you are asking for trouble without that screen.
You have seen how fine those holes are.
As for the problem, good chances you have a split in the hose just where it goes through the grommet.
OR
You have the feed & return tubes transposed.
The return hose goes about 1/4" into the tank past the grommet.
Take the tank cap off and pump the primer.
You should hear the returning fuel "peeing" into the fuel tank.
If not, or you hear it "blowing bubbles" then the intake and return lines are on the wrong carb spigots.
Don't feel silly, we have all done it before.