New guy here with a 86 Yamaha G1

[dcolliau]

I don't know if this is the right place for an intro but here goes. I found this forum when searching for G1 info. I am in Michigan, retired, not by choice. I have a back ground in plastic mold making and design and general tool making. I have been into cars most all my life. Currently I have a 51 bullet nose Studebaker , a 47 Dodge COE and a 92 S10 with a V8. I have been looking to get myself a cart for some time and finally found this one.
I have some questions I really need answers to. I have looked on the Yamaha web site but I am not able to find what I am looking for. What lines for the fuel and fuel pump hook the carb and crankcase? What lines for the oil pump hook to the pump and the crank case?
I put a new jug and piston in this. It runs but only if I choke it.
Should I get a good spray of fuel out of the pump? If not what am I looking for?
Thanks in advance,
Don Colliau

[Honorstick]

Welcome Don, I'm also from Michigan. I don't have the answers for you but I'm sure somebody will be along to help. Mines a 92 G9 and I'm still learning about that one.

[nwarren9]

welcome, fellow Michigander,

On my G1 I used automotive rubberized fuel lines works grate and hose clamps.

have some questions for you

Due you still use the oil injector system? are the oil lines still attached to carb or not?

due you think the fuel pump is stock? can you see the arrows on the pump?


G1 used a type of vacuum system to work the fuel pump. Note if you doe not have very good oil seals there is no way a G1 motor will never work correctly.

fuel lines ---this information is out of the G1 repair manual ---

1) line running from left side of pump to the back of block ( under the carb to the fuel pump) this is a vacuum line

2)the line to the fuel tank to pump tie in at bottom of pump.

3)line from the top of fuel pump to carb.



please posting some pitchers of your cart would relay help.

[slonomo]

Ok, you asked for it.....

The G1 uses a vacuum pulse off of the bottom end of the engine to deliver power to make the fuel pump push fuel. Yes it should squirt out pretty good, although not 10 feet, but a pretty good squirt and decent volume. First check the vac line that goes from the fuel pump to the bottom of the engine. Replace if needed.

Check the fuel pump itself, they can be disassembled and cleaned, look at the "sticky" at the top of the main yamaha gas page. You can buy new yamaha part for 50 or 60 bucks, or do like I did and buy the universal tractor fuel pump at your local lawn and garden shop for like 15 bucks. Works great.

Check your carb and clean/rebuild as needed. These carbs are tiny and the fuel and air passages are super tiny. Use torch tip cleaners to clean out the small holes. If it's all corroded up inside, replace it.

Check your fuel and your 2 cycle oil reservoir. Make sure your oil pump is working by removing the feed line and see that it pumps oil. If not, disconnect it and mix your own fuel. The manual calls for 150:1-300:1 believe it or not! Most of us here run 50:1 - 80:1 somewhere. Do what you feel is right.

Do as much reading as you can here on this forum. Do tons of searching and use different search headings to find what you are looking for. I found almost everything I needed here to get mine up and going, and it was a basket case!

Good luck.

[nwarren9]

slonomo relay know his G1,

I would like add one little thing that caused me a lot of trouble and it is simple fix "the fuel line in the gas tank it self just at the very upper portion of the line crack and would not allow suction" I ended up running fuel line from fuel pump to the bottom of gas tank with a new gas filter an used silicon around the opening of the tank. I have a ugly cart that works some of time !

[dcolliau]

WOW! Thanks for the fast replies. I will go thru the steps and check the lines and vacuum. I may have to put seals in this. Hope it is not too much work. I will post pictures of the old thing later.
Don

[RSP]

Welcome Don, Im also from Michigan and I have club car, and ezgo but pistons are pistons, carb are carbs and I`ll help if i can.

[nwarren9]

dcolliau

removing the primer clutch is the only challenge to dissembling a G1 motor. Your local machine shop can help or purchased on ebay a puller.

http://www.ebay.com/itm/Yamaha-Gas-G...58376f&vxp=mtr


about oil injection: when I rebuilt the motor I gave the pump the deep six. It takes only 2 min to mix up 6 gal of gas and lets say you use 18 gal in a summer that's 6 min a year. to redue you motor on the conservative side 6 hr. and over $300.00 in parts. not worth rolling the dice but that's my two cents only.

keep us up dated
have fun

[dcolliau]

Did some more work on this today. I can suck on the pulse side of the pump and it works. I seem to have a lot of pressure from the crankcase pulse line but I am not sure about vacuum. When I take the line off to the carb I only get little spurts of fuel. Suggestions?
Thanks,
Don

UPDATE
Just got done puling the flywheel. The seal is shot on that side. Yes I will replace both sides.

[nwarren9]

slonomo is correct in saying it is a pulse system not a true vacuum. here is some tricks you could try.

1)try running an bypass gas line from inside of tank to the fuel pump bypassing the existing fuel line and filters. If this gives you more gas probable one or more things. some thing in your tank or filter and or some thing blocking your fuel lines.

2)gas flow dose not change look at fuel pump it self. some times they get build up of white oxide.

I would suggest run a search on "G1 fuel pump", I have read an excellent wright up about this very subject.

this is my suggestion: I am just an old farm boy and that all !
good luck

look at this
http://www.buggiesgonewild.com/gas-y...fuel-pump.html