G1 should run but won't

[butterball]

I am new to this group, and new to 2 stroke engines. I do have a good bit of experience with old car/truck, and motorcycle 4 stroke engines, but none at all with 2 strokers.

I recently bought an old Yamaha 2 stroke golf cart, early 1980s vintage. It has been sitting for a few years and does not run. The first thing that I did was clean the carb, which appeared to be in good condition. I checked the compression, and it has 105 PSI compression. It has CDI ignition which is apparently working OK, as it has good hot spark. I checked the timing and it is right on. The fuel pump does not function, so I rigged up a gravity feed temporary fuel tank. I also tried a little raw gas, and sprayed starting fluid through the carb, and also through the spark plug hole. I have never gotten it to fire a single time. With compression, properly timed spark, and fuel, it seems to me that it should fire and at least run a little. With no experience with 2 strokes, I don’t really know what my next troubleshooting step should be. If any of you can guide me to at least a little beyond where I am now, I will greatly appreciate it.

[wthompson]

compression is low, but it should run. If the fuel pump is not working i would start by replacing it and the fuel filter. premix the fuel and don't trust the oil injection! The 2 stroke yamahas are notorious for bad crank seals and thats probably where you are loosing the compression. Also, there are a lot of linkages for the carb and governor on these carts so ger a manual from ebay. post the serial number and i could help you more.

[butterball]

What oil/fuel ratio should I use for this? The serial # of my cart is J31-107518. Actually, I can't tell if the last digit is an 8 or a 3, but that probably doesn't matter for now. According to what I looked up on the web, that makes it a 1985 G-1 series. I did buy and download manual, off of the internet. The pictures aren't real great, but are a whole lot better than nothing.
Thanks,
Mike

[wthompson]

40:1 . Is the plug wet with fuel after cranking it?

[butterball]

I don't think that the plug was wet. I will try again to double check. I will mix some 40:1. What I have been trying is 32:1. I'll get back to you soon.

[Larry1950]

Yep! Compression is too low.

[butterball]

OK, I tried it again, with my gravity feed tank connected directly into the carb. Yes, after cranking it with and without the choke, the plug does become wet. It still won't run though. Since this cart hasn't been run for a couple of years, there probably won't be any visible leakage around the crankcase seals. So, how do I determine if they are bad or not?
Thanks
Mike

[Larry1950]

Check the muffler, it could be plugged with anything from mouse nest to mud dobbers. Just loosen or remove the muffler and see if it fires. While at it look in the exhaust port to see if the piston is scored or carbon build up. Remove the carb and reed valve (if it has one) look again to see if the piston is scored. If the plug is wet its not firing or compression is too low, or exhaust is plugged. It is possible to recondition the seals by filling the crankcase with ATF, let it set for a few days then drain the ATF (automatic transmission fluid). I have seen where a plug fires nicely, but under compression the coil fails.

[butterball]

OK, I removed the muffler. It does not appear to be plugged, at least not where I can see. The valve operates nice and freely. The piston is badly scored vertically, in the area of the exhaust port. I pulled the head off when I saw that. The cylinder wall is slightly gouged in the same area, but not nearly as bad as the piston. So now I'm not sure how deeply to dig into this thing. Is this a common issue that is likely to be fixed by doing a top end job, or should I do a complete overhaul top + bottom. Also, are these old carts worth it??

[Larry1950]

Its broke! New piston, rings, cylinder. That old of a motor probably main and rod bearings, Lottsa bucks.

http://www.buggiesunlimited.com/prod...FaZaMgodqB8AnA

http://www.bakerscartsupply.com/engi...t-9093-b29.php

[butterball]

I removed the cylinder. It is trashed, same as the piston. So, I need a new top end. I also checked the side to side sway at the top of the connecting rod. The manual says that it should be less than .79 inches, which actually should read .079 inches. There is a misprint in the manual. Mine measures .075, so it's just barely within tolerance. There is no noticeable up and down play, and nearly no side to side play. So, I assume that the bottom end is useable. (opinions would be appreciated). Also, is there a good way to flush out (clean the inside of) the crank cases without removing and disassembling the bottom end? Also, please give me the names of a few good places to buy parts for a G1

[Larry1950]

Does the crank and rod rotate smoothly with no noise? You can fill the crank with ATF (automatic Transmission fluid) This will do 2 things, it will flush out the lower end and soften the seals. However given the age of the motor you would be money ahead by doing a complete rebuild or at least new seals.
Is the cart one that the motor runs in reverse when going in reverse I believe that is what you have,or does it have a transaxle to control F/R. I am not a a fan of 2 strokes. Might want to look into doing a conversion. You can get a Predator 346cc 11hp electric start from Harbor Freight for about $350.00. Anyway keep you options open. I have dealt with Buggies unlimited with very good results.

[wthompson]

the engine runs in both directions for f&r. transaxle does not shift. check around and see who rebuilds golf cart engines in your area. We have J&M in augusta, Ga this is what they specialize in. link to there site you can check ti out. http://www.jandmgolfcarts.com/engineprice.htm

[butterball]

Yes, my engine runs in both directions. The crank rotates smoothly. I will definately replace the seals, when I do the top end. The Predator engine swap is interesting. Is that a common and popular thing to do?

[Larry1950]

Won't work unless the transaxle has the F/R

[butterball]

OK, good to know. Where should I buy my top end parts.

[wthompson]

i would get parts from yamaha dealer. my 2 cents.

[butterball]

I have ordered top end rebuild kit. In the meantime, I filled the crankcase full of ATF just to flush it out, and hopefully soften the seals. The ATF immediately began pouring out of both crankcase seals, just about as fast as I could pour it in. I guess pretty much tells the story about the seals, so I ordered them too.

[wthompson]

let us know how it goes.

[butterball]

I have received my new parts, but I need to get the ATF out of the crankcase before I start. I can't find a drain plug, so either I missed it or there isn't one. Please educate me on the best way to drain the ATF. Do I need to remove the engine? I hope not

[wthompson]

there is not a drain plug. can you draw it out with a turkey baster? what you leave will burn out.

[butterball]

I have now removed the engine from the cart. I have a new top end and new crankcase seals to install. The manual calls for several special tools for disassembly of the magneto, clutch, and crankcases. Since this is my first golf cart, I don't have any of the special tools. I don't want to buy any more of them than necessary, since I may not have any future use for them. Can any of you guide me here. I'll go ahead and buy the ones that are absolutely necessary. Where possible, however, I'd like to improvize, or substitute, or fabricate, etc. Any help, guidance, or advice will be much appreciated.
Thanks,
Mike

[wthompson]

special tool i can remember are bearing puller to remove bearings from crankshft and impact screw driver for phillips head screws that hold two crankcase halves together. get some yamabond 4 to reseal crankcase halves.

[butterball]

I now have everything apart, and will install new seals today.

[Larry1950]

Be sure to coat the piston and cylinder with oil. Dribble some oil in the wrist pin, crank, rod bearings and new seals. Don't want a dry start. Might want to mix 32:1 or even 24:1 for the first hour or so. Keep a spare plug handy til' it clears out.

[butterball]

Success, Today, I reinstalled the engine and re-connected the wiring. It fired right up using a temporary gravity feed gas tank. Running it that way, I discovered that the fuel pump is working OK, but the oil pump is not working at all. So, I think that I'll just premix my fuel and oil, and not use the automatic oiling system. I assume that I should block off the oil input port on the carburetor. Is this correct? Also, what would you guys recommend as a good all around ratio for the fuelil mix? This list has been a big help to me in rebuilding my first golf cart engine. Tomorrow I'll re-install all of the plastic shroud covers and it will be finished. Thanks to all of you.

[Larry1950]

Congrats on your engine rebuild Yes plug off the oil port to the carb and run premix. I would run at least a 32:1 premix for at least 2 hours running time, and be easy on it for that time. You should be able to run 50:1 after 2 to 3 hours running. Happy Happy Happy!

[wthompson]

Great Job!! Your right, don't use the oil injection system. 40:1 is what i run.

[butterball]

Today I took a long ride in the old G1, and it ran great. I just have one more question. My fuel pump will lift fuel up into the carb, but it won't pull it from the tank down to the pump itself. Is that normal? I forced a little fuel into the filter and from there it seemed to siphon enough fuel from the tank to keep it running. What do I need to do to insure a good siphon action from the fuel tank to the pump

[Larry1950]

The fuel pump should draw from the tank, if not you have an air leak somewhere in the sipe or fuel line before the pump. Also check for a plugged vent in the gas cap. The fuel filter will usually have some air in it. Replace the vacuum line from the crankcase. You might want to get a new Makuni fuel pump, you can get one for about $20.00 for a single pumper if you look around.
http://www.powersportsplace.com/part...Fe1AMgod5UEAvA

[butterball]

I wish that I had removed the pump while I had the engine out, but didn't even think about it. I replaced the vacuum line, and checked & re-clamped all of the other lines. Nothing changed. I guess that I'll go back and remove the pump. The bottom mounting screw looks nearly impossible to get to. Is there a trick to getting it out, or do I just need to remove the engine again?

[Larry1950]

Frankly I wouldn't worry about the old fuel pump. I would just get a new Makuni and re plumb the entire fuel system with new lines and filters. Save your self a bunch of headaches.

[butterball]

I did just as you recommended. I installed the new pump, and did the re-plumbing, and she runs great. This site has been very helpful. Thanks to you all.

[Vince1982]

At any time did you notice if the motor would turn over better with spark plug out then it did with it in ?