Working on a Yamaha for a Good Friend

[Getter-Done]

I am working on an Older Yamaha for a Friend.

I hope I am in the correct Forum section

I don't know year or model.
Just that it is a Yamaha

I have been trying to find a Serial number or Model # tag location

Here is the Issue, The Engine will Crank (Turn over) very strong.
It will not start.
He says it is the fuel.
I will check the spark and compression and all that stuff,
After the rain storm.

Would like to find the I. D. Tag


Thanks in Advance for the help.
Here is a picture below.
yamaha.jpeg






.

[CP241]

That’s a G1. Slo or a couple other guys are much more familiar with those… but also could be crank seals

[Getter-Done]

Thanks for the info CP241

The rain has passed.
I still have some daylight light
So I will go do some testing,



.

[Getter-Done]

I found a number in the back left frame behind the bumper.
It is getting Spark to the plug.
It has about 80 lbs compression.
It burps and hiccups and small backfire with a small breath of starting fluid.

Here is some pictures.
gc1.jpg

gc2.jpg

gc3.jpg

gc4.jpg

gc5.jpg


.

[Getter-Done]

gc6.jpg

gc7.jpg

gc8.jpg

gc9.jpg

gc10.jpg



.

[Getter-Done]

gc11.jpg


This piece below stayed with the plug when I took the wire off.
I put it back in.
Seems okay.

gc12.jpg





.

[slonomo]

Starting fluid....not good for 2 strokes. It doesn't have any oil in it and will deglaze your cylinder walls. Rule of thumb....if it won't start on gasoline, it has a different problem. I use a spray bottle with the proper fuel in it and spray it in the carburetor while it's cranking, best way to diagnose a fuel issue.

Start with the basics: Air, fuel, compression, spark. Once you know where you sit with those we can get into it further.

G1's are excellent carts, very durable and run excellent when in good condition. These are low compression engines and the crank seals are very common failure points. Two other common issues are the fuel pump and the fuel pickup tube in the tank cracks. The fuel pump can be replaced with an off the shelf Briggs fuel pump and it works quite well, they like to pull the fuel so mount them up closer to the engine. Install all new fuel and vacuum lines, they rot and leak. I'm also not a fan of electric fuel pumps, just not necessary when the cart is factory and things are maintained. The fuel pick up tube is a factory plastic straw in the tank and the last time I checked it was available, but you can also use a long section of fuel hose instead, just make sure you have enough inside the tank to reach the bottom, worked well for me for years. But remove the tank and flush it out first.

Also read the sticky for the G1's on the main page.

[Getter-Done]

Thanks slonomo

Yea no more starting fluid.
I did a mist for about 3 or 4 seconds.

I will read the Sticky

From your info ,I think I will start with the fuel pump next.

Then go to the fuel tank.
The fuel tank is full of fresh fuel.
But IDK what is on the bottom

Thanks for your help


.

[Getter-Done]

Okay
So far, fuel pump not working.

I chose to take the carb off to get my fat hands in too remove the fuel lines from the pump
I pulled the carb bowl , It looks clean

I was going to deal with with hot wire thing later

Then I realize , That big goofy tin can on the side of the tank
Is an electric fuel pump That someone put on there
It was not even wired correctly
So it will work, But wasn't working the way it was wired.

I'm heading to town to see if I can find a Briggs & Star. Pump.

BTW
I can hear the tube hitting the side of the tank.

Thanks for all the great pointers slonomo

[CP241]

An easier way to check crank seals vs. the carb cleaner method, especially if It won’t start at all, disconnect the pulse line running from the engine block to the fuel pump. Press the pedal and spin the engine, with your finger on the end of the line. It should alternate suck/blow quickly and have a decent amount of pressure you can feel. Many times (depending how bad crank seals are) if it’s bad enough to not start, you won’t have any pulse in that line.

This pulse is created by the up/down motion of the piston creating negative and positive pressure within the crankcase. On a 2 stroke engine, this is the same pressure that also draws the air/fuel mixture in from the carb. When the crank seals are blown out, it creates a massive air leak and all the crankcase pressure/vacuum leaks through those seals, as they’re the path of least resistance. This not only kills fuel, but sucks in a ton of unmetered air, making the engine run incredibly lean until it doesn’t get enough fuel in to run at all.