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Engine Starving For Fuel
Hello, It is a 150cc Peace Scoooter. Fuel is in the carb. Everything else checks out O.K. although I have not performed a compression check. One day it was being run in the rain and just died. Valve adjustment set at .004". Engine may start and run short period with carb spray shot into Intake Manifold through vacuum fitting. A member on this site has stated that Low Float Bowl Level (fuel not covering the Pilot Jet and/or Bad Timing) are 2 things to check if the engine will not induct the fuel from the carb. Does anyone have anything to add to this? Thanks.
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try taking off gas cap see if you have a vent problem also has you scooter been sitting for a long time with ethanol gas if so drain out tank and try to find real gas without it and above 91 octane. But if it been sitting for a while you will need to open carb and clean the low speed jet and high speed jet this isn't a really hard job and there are a lot of u tube videos showing how to do it.
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Crawford, Thanks for the reply. I have had the carb off 2 or 3 times already. Sprayed the orifices with Gunk Carb Cleaner/Choke Cleaner aerosol spray 2X. Jets and emulsion tubes are clear. Fuel enrichment needle is at correct setting for cold (approx. 3/4"). I have checked the carb float setting and the engine timing. Scooter has been sitting, but fuel only couple weeks old. Remember, fuel is IN the carb; it just is not going into the engine. Spark plug is always dry, not even smelling like gasoline. Currently there is 87 Octane with Ethanol in the tank.
I have tried and tested many things. Next up is a compression test. |
It does sound like a carburetor problem. I'd use the up in the air kickstand and try to keep it running with the carburetor spray and see if the engine won't run on it own when warmed up a bit. I finally gave up on the carburetor on a 50cc and ordered a new one carburetor. 20 bucks and that solved the starting and driveability problems. Whatever the problem was with the old carb, I never found it and I must have had it apart 5 times.
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Hi Roscoe The feeling and thoughts of most are that the stock Chinese carbs are junk. I have never been fond of any Chinese engineering OR parts and find them lacking in too many respects. I have been working on small engine stuff for several years. The electrical parts on these scooters are not that great, leaving much to be desired in the way of durability, as the price of replacements indicate. I will probably try another carb. A Keihin would be great but I do not like the fact that they are almost twice the cost of their Chinese counterpart.
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A Chinese carb is plenty good enough. I have a Mikuni on my atv, and Keihin's on my Ural. My scooter carb has been trouble free (save one auto enricher), through 6 riding seasons, and 5 winter hibernations. I would never buy anything but a cheap CVK carb for a gy6.
You say you've been working on small engines for several years....me too, bought my first Honda bike in 1965.....so I'm sure you know that ethanol blended gas is the number 1 reason for engine trouble in small, carburetored equipment. Stay away from it, maybe add a little MMO to your gas, and run thousands and thousands of miles, carb problem free. |
Hello rks Thanks for jumping in with us. I concur about the ethanol. I will try your advice as well. I have used fuel with additives I put in before including the infamous MMO. I am going to try a new Chinese carb and see if anything changes. I will be checking the compression soon as well. Thanks again.
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Does is have a vacuum control valve if so is it working or is it getting good vacuum? This valve is in place of a on off valve and some times listed as a pump.
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Hello Irish, I am aware of that site and have referred many to it on a couple other forums. It is https://www.pure-gas.org/ . Yes, there is ethanol-free gas available in MY area. Still waiting on my 10mm compression tester fitting. It is sitting in the post office behind my home because they did not deliver today (Saturday)...thanks to Irma.
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Hello This is NOT going to be one of those threads in which we do not FIND OUT the end result or outcome. Those threads are downright annoying. I have read way too many of them in my day. No sir; this thread will have a PROPER beginning...and a PROPER ending; ONCE we find out what the exact cure for the fuel starvation problem is OR was.
Compression test yielded about 168psi on the gauge. Not a cheap gauge, I think it is a Snap-On. Throttle cable broke. I shall be back once all is assembled with new cable, new carb and a new starter clutch along with a new stator (not starter) and let YOU GUYS know the result. |
UPDATE: Hi Guys Scooter still not starting. Gas is coming out the air filter side of the new carb. I am leaning towards a timing and/or valve issue. I got it to run however when I sprayed Carb/Choke cleaner directly into the cylinder. It did NOT run when sprayed into the carburetor. If scoot sits about 24 hours, it will immediately start up and run about a second or two and die. I figure that is from the gas fumes emitting from the carb and seeping into the engine. I think I will need to pull the cylinder head for an inspection.
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I'd try a known good spark plug, make sure gas runs out the drain tube when cranking. If it has compression, spark and fuel and runs at all it ought to keep running.
Also make sure you didn't get a "bad" tank of gasoline. |
Hi Roscoe Today I pulled the cylinder head to inspect the valves. They were OK, but the Timing Chain Guides were ragged and the Top one that is bolted in the crankcase was rubbing against the side of the chain; somewhat dislocated. I am aware of your suggestions. The engine may have suffered mis-timing as the automatic chain tensioner was pushing against the upper chain guide that was out of position. The chain itself is fine. This is a severely abused machine and every time I remove any part to inspect it...almost every part needs repair or replacement. For example...the O Ring on the Intake manifold was shrunken and dry rotted providing no sealing benefits whatsoever on the cylinder head. No bent valves, no broken timing chain; but severely worn and partially damaged chain guides along with a damaged drive belt were found on it today. The O Ring on the Intake manifold was suspect for quite some time. This is a 2014 scoot with many miles on it.
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