Yamaha G1 Will only run if spraying gas in carb

hotrod-101 · 12-09-2010, 11:50 AM

I got a golf cart gave to me and it looks rough but has potential. The problem is I can only get it to run if I spray sum WD40 or gas into the carb. Everything checks out good. It has 120psi compression so it don't appear to be worn out. I eleminated the fuel pump and put on a gravity fed test tank. The oiler leaks so i will not be using it anyways and just mix my oil and gas which i would probrably do regardless. I have taken the carb off 3 times and disassembled it and cleaned and cleaned and cleaned. LOL. I thought it may be sucking air so I took off the intake and checked for cracks but everything seemed fine and the reed valves lookd good as I figured they were or the compression would have been bad. This is where I'm at on it now. I got to get new gaskets for the intake to put it back on.
Since I don't have a manual and really hate to spend $50 on one i was wondering if you guys could tell me what that black airbox looking thing is that has a hose going into the intake and a smaller hose going into the crank. It appears to be ok and dont have any cracks or anything but was wondering if it may be letting it suck air. I have place my hand over the intake and it seems to be sucking in pretty good so unless there is some port in the carb that I can't get to to clean or it is sucking air through that black box then I don't know what's wrong. I am usually pretty good mechanic on 2 and 4 stroke engines from small chain saws to v8's but this little one is kicking my butt. HAHA.
The thing is is I don't want to spend alot of money on this engine because i was going to put a snowmobile engine in it but If i can get it running like it is then I may leave this on in there for the time being because I'm just going to make it a hunting buggy anyways.
Thanks for any advice,
Hotrod-101

hotrod-101 · 12-09-2010, 05:51 PM

I may have found the answer in roasting the muffler to get the many years of sutt out of it. I did notice when I took off the muffler and turned it over that it seemed to suck in the intake harder. With the choke on it would try and run a little so hopefully this is it. If not then the crankcase seals my be bad. If anyone has a repair manual for a G1 and would be interested in selling it then PM me.
Thanks

skarp · 12-09-2010, 07:05 PM

Sounds like you may have bad crank case seals??

Spray starter fluid down behind the primary sheeve and see if it starts...if so...bad crank case seals.

Hope that helps!! :)

hotrod-101 · 12-10-2010, 10:12 AM

I will give it a try. It will be a few days before I can get back to working on it but I will post back when I get a chance to try it. Thanks skarp

BreezyGreen1 · 12-26-2015, 08:01 PM

If I block the intake with my hand while cranking I end getting fuel mux coming out near the clutch, maybe crank seal? It was dry before I did that. Is that a bad seal or was it pressure trying to get out because I blocked the intake? Could this maybe indicate a blocked exhaust?

slonomo · 12-31-2015, 08:42 AM

wow old thread lol...

I saw your other thread, I'll post there....

12-09-2010, 11:50 AM	#1
hotrod-101 Not Yet Wild Join Date: Dec 2010 Location: Southeast tn Posts: 12	Yamaha G1 Will only run if spraying gas in carb I got a golf cart gave to me and it looks rough but has potential. The problem is I can only get it to run if I spray sum WD40 or gas into the carb. Everything checks out good. It has 120psi compression so it don't appear to be worn out. I eleminated the fuel pump and put on a gravity fed test tank. The oiler leaks so i will not be using it anyways and just mix my oil and gas which i would probrably do regardless. I have taken the carb off 3 times and disassembled it and cleaned and cleaned and cleaned. LOL. I thought it may be sucking air so I took off the intake and checked for cracks but everything seemed fine and the reed valves lookd good as I figured they were or the compression would have been bad. This is where I'm at on it now. I got to get new gaskets for the intake to put it back on. Since I don't have a manual and really hate to spend $50 on one i was wondering if you guys could tell me what that black airbox looking thing is that has a hose going into the intake and a smaller hose going into the crank. It appears to be ok and dont have any cracks or anything but was wondering if it may be letting it suck air. I have place my hand over the intake and it seems to be sucking in pretty good so unless there is some port in the carb that I can't get to to clean or it is sucking air through that black box then I don't know what's wrong. I am usually pretty good mechanic on 2 and 4 stroke engines from small chain saws to v8's but this little one is kicking my butt. HAHA. The thing is is I don't want to spend alot of money on this engine because i was going to put a snowmobile engine in it but If i can get it running like it is then I may leave this on in there for the time being because I'm just going to make it a hunting buggy anyways. Thanks for any advice, Hotrod-101

12-09-2010, 05:51 PM	#2
hotrod-101 Not Yet Wild Join Date: Dec 2010 Location: Southeast tn Posts: 12	Re: Yamaha G1 Will only run if spraying gas in carb I may have found the answer in roasting the muffler to get the many years of sutt out of it. I did notice when I took off the muffler and turned it over that it seemed to suck in the intake harder. With the choke on it would try and run a little so hopefully this is it. If not then the crankcase seals my be bad. If anyone has a repair manual for a G1 and would be interested in selling it then PM me. Thanks

12-09-2010, 07:05 PM	#3
skarp Gone Wild Join Date: Nov 2009 Posts: 250	Re: Yamaha G1 Will only run if spraying gas in carb Sounds like you may have bad crank case seals?? Spray starter fluid down behind the primary sheeve and see if it starts...if so...bad crank case seals. Hope that helps!! :)
skarp Gone Wild Join Date: Nov 2009 Posts: 250

12-10-2010, 10:12 AM	#4
hotrod-101 Not Yet Wild Join Date: Dec 2010 Location: Southeast tn Posts: 12	Re: Yamaha G1 Will only run if spraying gas in carb I will give it a try. It will be a few days before I can get back to working on it but I will post back when I get a chance to try it. Thanks skarp

12-26-2015, 08:01 PM	#5
BreezyGreen1 Not Yet Wild Join Date: Dec 2015 Location: Leicester, MA Posts: 9	Re: Yamaha G1 Will only run if spraying gas in carb If I block the intake with my hand while cranking I end getting fuel mux coming out near the clutch, maybe crank seal? It was dry before I did that. Is that a bad seal or was it pressure trying to get out because I blocked the intake? Could this maybe indicate a blocked exhaust?

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12-31-2015, 08:42 AM	#6
slonomo Searching for The Way Join Date: Oct 2009 Location: Medina, Ohio (NEOHIO) Posts: 11,441	Re: Yamaha G1 Will only run if spraying gas in carb wow old thread lol... I saw your other thread, I'll post there....

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