98 Vmax 600 sx twin OIL PUMP question

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biglsells

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Jan 14, 2012
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Grand Rapids, MI
Just wrapped up another rebuild on my sled and had a question about my oil pump. In my last post I showed pictures of the blowup and some people said it looked like symptoms of no / minimal oil. Ever since I have been wondering how to test the oil pump while re-assembling. I did not test it however I made sure it was set correctly. Snowmobile started just fine but I shut it right off.

There is a line from the oil tank to the bottom of the oil pump and then a line off the side of the oil pump that goes under the carbs and disappears under the tank. Question - is this pump supposed to be pushing oil up through this line? I would assume so but when I took it apart to pull the motor and I pulled that line off the side of the pump gas started pouring out of it until I plugged it. There is a bubble of air in the hose after I put the line back on the side of the pump and while it was running the bubble never moved and the line is just full of gas. Whats going on? Is it safe to assume the pump is shot? I heard that they fail wide open but honestly it looks like its doing nothing. I pulled the little screw out of the top of the pump and oil started coming out so I know the pump is getting oil just fine.

Any help is greatly appreciated.
 
Premix enough fuel in the tsnk to test and make sure thst the pump is working. Try idling the sled up some while making the arm on the oil pump think that you are at wide open throttle you should see the bubble move slowly toward the feul pump as tje oil and gas are mixed in the pump.
 
Do I need to first push all that gas out of the line coming from the side of the oil pump and leading to the fuel pump and fill it with oil?
 
Would think it would be wise but I don't know how fast it will want to refill... Try the premix method first, it is an excellent insurance policy incase the pump is no good, and if the pump works you will know as the sled will smoke a bit while running.
 
First don't fill the tank completely with pre mix fuel, only use 2-3 gallons just to make sure all is well at first, then all you will have to do is fill the tamk completely full and you will have no issues.
 
biglsells said:
Is there an easy way to get all the non-pre mix fuel out of the system and carbs?
Click to expand...
If you have access to a Mityvac vacuum pump they have a canister that comes in the kit which is for bleeding brake technically but would draw enough vacuum to pull the fuel through the line until you get the premix into it. There are drain screws on the float bowls but I wouldn't call them easy to get to. Other than that just disassemble everything and drain it as best as possible.

Jeremy
 
yep, pump appears to not be doing anything at all. Does anyone know where I can pick a used one of these up cheap? I can't find any at all on ebay for my model sled.
 
Check to make sure of where the problem is before you replace the pump. It could be a drive problem like a broken belt - which would mean that the water pump also is not turning, but that could be part of your problem.

There is an access hole to check the belt. Remove the pump and inspect the drive. There is a tab on the pump that fits into a slot on the drive, the tab may be rounded off.

If everything else is okay, take the pump apart and check it. You might find something that is easily fixable.
 
PZ 1 said:
Check to make sure of where the problem is before you replace the pump. It could be a drive problem like a broken belt - which would mean that the water pump also is not turning, but that could be part of your problem.

There is an access hole to check the belt. Remove the pump and inspect the drive. There is a tab on the pump that fits into a slot on the drive, the tab may be rounded off.

If everything else is okay, take the pump apart and check it. You might find something that is easily fixable.
Click to expand...
This, have you also checked your filter to make sure oil is actually flowing through the tube to the oil pump? The pump can't work if it's got nothing to pump.

Jeremy
 
OK - UPDATE - I took the pump off, removed the line coming from the pump to the carbs, put my drill on it, held it at WOT and sure enough, oil started burping out of it.
Put the pump back on the engine, held at WOT and pulled the snot out of it, not a drop. I had the engine 100% apart for a complete rebuild and replaced the belt a couple days ago so I knew that the water pump was spinning. Took the pump back off and came inside and looked up pics of ones that have sold on ebay and thats when I noticed that sure enough, the flat tab portion coming out of the oil pump that slips into the slit on the water pump was completely worn! The engine has not been spinning the oil pump at all, this explains a ton, ie. third rebuild. What would cause that to wear down like that? This sled only has about 4000 miles on it.

Anyway - I need a new oil pump and don't see any one ebay right now. Anyone know where I can get one cheap? p/n 8CR-13100-01-00

thanks for all the help, much appreciated.
 
Or you could start a new thread in wanted section. I read a ton of ads and didnt find what I was looking for, posted in wanted and WAA LAA! I dont know about your vmax but my srx has a vent tube/hose that looks like it disappears under tank but actually runs up to under bar pad.
 
Thanks to everyone for their help, got a new pump, everything is working like a dream. The drive tab on my pump was indeed bad, another user sent me one and the tab was perfect! I love this forum!
 
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