"Dry Carb" Restarting
 

Okay.... so I have too many toys to run them regularly enough to keep carbs "wet", so I am FOREVER wrestling with the stinkin' "dried out carb" re-prime to get the restart. I asked about this one time, and think, and got nowhere.

SURELYthere is someone here with a "sure fire" guaranteed solution to letting these things sit. Even on chainsaws and weedeaters and blowers, after sitting a season, it's "choke, pull, start".

What's up with these airplane gassers that won't do the same thing????

HELP!!!!!!!</p>

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well, one difference is on a pull start you're turning the engine over at least 5 times instead of one during a flip.</p>

another is most airplanes have a good 3 or 4 times the fuel line length, further to move the fuel.</p>

that's all I got right now</p>

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it must be that yellow oil bottle!http://www.rcuniverse.com/forum/js/f...spinnyeyes.gif just thought I would get that started.

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I know the Ryobi's use a finger pump, I bought 6 for $10 on ebay, that actually sucks fuel through the carb then pumps it back to the tank. That sucks through the carb took a while to figure out.:( A lot of the carbs have a brass tube that is crimped closed, that's where you would put the pump.

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That's REAL helpful. Thanks for nothing, Ken.
http://www.rcuniverse.com/forum/js/f.../msn/angry.gif

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I think the issue is the pump diaphragm on the "wet" side dries out, so there's nothing for it to pump. Plugging the carb throttle plate hole doesn't get it either; all that does is over-prime, then flood.

I put a check valve in one engine's inlet line this morning; will try that and see what happens. Surprisingly, it runs okay, and I didn't need to readjust the carb, so the check valve isn't restricting flow in the "right" direction, anyway.

RE:
 

That works the same as the check valve in a smoke system. Generally works just fine until they sit for a long time. Then, like anything else, they can gum up and fail to open...

Used to be you could run an engine dry then flush the carb with straight gas, or even alcohol, and things would work ok for long term storage. The idea was to flush the oil out of the carb since that's the component that generally causes things to stick after periods of long storage. You almost can't buy straight gas anymore.

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Understand, Pat. What about pumping fuel in the vent line to "pressurize" the tank for a few flips?

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I have tried that Bob and it doesn't work. I think the flaps in the walbro pump need the freedom to move in two directions. Even with the tank pressurized the fuel in the line would not move until the carb was "wet".

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Okay, Doug....so what do you do, then?

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I had to take the cowl off the re-prime it. Pain in the butt. On the engines with a pulse line I shoot a little fuel directly into the engine by hooking my fuel line from my fuel can to the pulse line and inject fuel into the reeds. Then I shoot a tiny bit the other way through the pulse line into the carb. I just tried it for the first time a couple weeks ago on my new Python and it worked great.

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A whiff of ether sprayed into the cowl will get you going. Nice and easy.

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Not to start a brand war. So I will not mention the oil I use. But I've learned to put some of my 2 cycle oil mix into my power tools like pressure washers and gas air compressors and generators between uses because the additives in the oil I use allows extended storage. Some have gone a year or two between starts and start right up.  No issues with the gas engines in the planes either. So as far as I'm concerned find an oil with good storage additives to help rather than hinder your process. </p>

That said, when I need to prime a stubborn carb after a carb rebuild I'll block off the tank vent and pressureise the tank some to start prime.</p>

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Chain saws have the problem as well. That is why they have the primer bulb pump. Ryobi has (had?) a primer bulb fitted in the appliance housing that can be retrofitted to a plane. That would solve the problem.

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I know it sucks....... all I got is prime it again by removing the needles and squirting fuel into the holes. Let it soak in a bit and then another squirt in the needle holes. Put the needles back in and start it. Tune accordingly.

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My GAWD!!!!!!!!! Unscrew needles???? Ya gotta be pullin' my leg.... how in the #$%&amp; would you do that with needles that point DOWN???

Ether would be oil-less start; not sure which is worse.....but if someone can convince me it wouldn't harm the engine....

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I solder the hole in the choke and never have had a problem with starting after the plane sits for a month or two

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might also use some Seafoam in your gas . You may be getting more ethynol than wanted.

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Bob what a great post ,this is a big problem with gas planes when you cant fly them all the time ,i have a yak with a 3W ,when its running its fantastic, but leave it for a couple of months and boy you have a bad shoulder starting it ,what i have been doing is make sure the plug is easily excisableremove it squirt a small amount of fuel in ,and bingo it starts straight up , been doing this for years with no probs what so ever just take your time removing plug and cap.

Best Regards John

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ONly use non-Ethanol gas.
Soldered choke holes closed; choke plates are fully closing.

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Maybe mine haven't sat long enough, but I always just spray some gas into the carb and away it goes.  Helps I have a Jersey Modeler electric jug. Might have to do it twice, but not a huge deal.

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I never had problems with pump not pumping when dry but how about a big dynatron starter for drastic measures? It should work everytime..

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Jake - rear carb - 50cc buried in cowl, venturi opening in hole in firewall....so can't get to carb venturi.

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Awwww, you just have to be more creative;) As for the starter, if a carb is not drawing gas you better have a real big battery...

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Ain't NO way I'm ever hauling a starter again.
As for being creative....I don't mind being creative, once someone offers a solution that is consistently able to fix the issue.So far, a "priming bulb" sounds like the most practical, and I'm actually starting to think about how to get an injector tube fabricated to an external dot for squirting gas into the carb venturi. But would that get it past the reed bank???