Fuel Pump???

[engreps]

I have a 1989 Serial # K1589

How much should the fuel pump be putting out at cranking?

I have a very little pulse of gas when turning over.

Is the fuel pump bad?
I disconected the fuel line at the carb and turning over the engine I have very little gas coming out. I can take a spray bottle filled with gas and spray into the air filter and it will run as long as you are spraying gas into the inlet.

[DOOmsman]

In the gas yamaha stickies you will see a thread fuel pump.
It shows how to clean the pump, they get crudded up.

[scottyb]

They pump out about 10 times what you describe Before you open the fuel pump check to see the pressure hose is good running from the bottom of the pump to the engine crankcase, that your filter & the pick up tube are clear.......

[engreps]

Thanks for the reply's. I will check on the hose from the engine and also the pick up. My luck it won't be something simple.

I have checked the gas filter. It was OK.
Air filter was bad. Must have not been changed in a long time.

First thing I am going to do is clean the engine with engine cleaner. It's so greasy and so much dirt you can barely see the side of the engine.
The previous owner must have only cleaned the front that you can see when lifting the seat.

[bauschracing]

The pump works off of pressure in the crankcase. If the seals are leaking, the pump will not work properly. Sounds stupid but take the bolt out of the elbow next to the carb. just above the reed valves and blow some type of smoke into the crankcase and look at the seals for signs of the smoke. If you see any seeping through, replace the crank seals. They are less than $10 for both of them. You just have to pull the motor, clutch and front cover and flywheel.

[engreps]

Originally Posted by bauschracing

The pump works off of pressure in the crankcase. If the seals are leaking, the pump will not work properly. Sounds stupid but take the bolt out of the elbow next to the carb. just above the reed valves and blow some type of smoke into the crankcase and look at the seals for signs of the smoke. If you see any seeping through, replace the crank seals. They are less than $10 for both of them. You just have to pull the motor, clutch and front cover and flywheel.

The elbow? Are you saying the intake tube the carb is attache to??
Could you use a little air pressure? How much pressure should should the seals hold???

[bauschracing]

Yes - between the carb. and the top of the motor. It might be where the oil injection fitting goes. My cart did not have the injection system on it. I would not use much air pressure, I had a backfire and then the engine would not run. I pulled out the engine and first found out that the head bolts were loose. I put rings in while the motor was out. Afterwords it would not crank. Not too much fuel pressure, so I pulled the bolt out and put some gas-oil mix in the hole and re-inserted the bolt. I turned over the motor and after the spark hit, smoke was seen at the clutch side seal. When I pulled the engine out and removed the flywheel, the seal was blown out of place from the backfire and had landed on the magnetic pulsar pick up.
Once I put these seals in, I had good compression and good fuel pressure. The engine runs like new.
These engines are no trouble to remove and can be removed in less than a hour with hand tools.
Mike

[engreps]

Mike

You may have just solved my problem. My cart also backfired and has backfired the last few times I used it. I bet you are right about the seals.

Can the motor be removed with out removing the body?

[DOOmsman]

Follow up, Scotty dog is right start with the simple stuff
first check the lines and such.
Take a compression reading, bad seals will give low numbers.
We tend to think the worst first.

[bauschracing]

Check the simple stuff first by all means. If you have to remove the engine it is not that hard. Remove the battery cables, fuel line, pulsar wiring(two wires on the carb. side), air cleaner, muffler and take out, loosen and remove the starter/gen assy. and set aside. Do not remove the wiring, choke, govener and accel. cables. take the coil wire off the spark plug and then there are 4 bolts on the pass. side and 3 on the drivers side of the engine. You only have to loosen the top bolts because they are in a slot.
There are threads on here showing how to remove the clutch and flywheel to gain access to the seals. Then just reverse to install.
I had my engine in and out two or three times.