[YAMFAM7]

Siezed the engine on my 1997 Venture 600. After letting it cool off, it did start again. Took off head and jugs to inspect pistons. pitsons have scoring on the intake side to suggest lack of oil ? How can I test the oil pump or check to see if its bad ?

 

[mosabi]

From what I understand when an oil pump fails it goes wide open, not closed. If this is a carb machine when did you last clean them? Sorry to hear of your luck.

 

[YAMFAM7]

oil pump

Thanks for the reply, Carbs are clean and the machine was moving at a good clip when she locked up.. There seems to be a small shaft on the pump that rotates and it does move freely.

 

[yamadad4]

lack of oil will usually show scuffing on the intake and exhaust side. if you havent cleaned the pistons up much is there oil inside(under) the piston itself?

water or snow ingestion will show up on the intake side. do the scuffs line up with the intake ports as well? is there large clean spots on the top of the piston's intake side where the carbon appears "washed off"? what were the snow conditions you were riding in?

on some of the higher mileage ventures, the connector for the oil pump drive would wear and misalign the shaft making it not work. it should be apparent when you pull the oil pump. a tounge and groove affair that would appear rusted, corroded or worn.

 

[YAMFAM7]

Yamadad, I checked the pistons and both of them are real dark brown evenly accross the top, no markings at all. The scoring marks cover a little less than half of the piston on the intake side.

 

[Dadbro]

first I would check the pump belt to make sure it is intact.
There will be a inspection hole.
Is the cable still functioning.
inspect to see it the hose off the oil pump is in good shape feeding the fuel pump, then the hose leading from the fuel pump to the bearings.
I dont know of to much that can go wrong with the oil pump itself, but then again I have never taken one apart.

Was this the first time out on the sled this year?
Where the carbs remove, taken apart and cleaned?
I seen a lot of problems arise when the jetting gets plugged.
I am not sure how much experience you have with snowmobiles and dont want to come across as being a know it all cause that I am far from that.
If in doubt I have read where sledders will run a tank of mixed fuel and also run with the oil reserve full and then check the oil consumption when you run through a tank of fuel. or say 25 liters of gas to 500 ml oil. Your should see at least 500 ml oil used out of the reserve.
Good luck.

 

[yamadad4]

Yamadad, I checked the pistons and both of them are real dark brown evenly accross the top, no markings at all. The scoring marks cover a little less than half of the piston on the intake side.

if the pistons have an oily film/residue up inside, the failure wouldnt be pump related. thats usually a good indication of oiling or not. the scuffing seeming limited to the intake side leads towards water or snow.

probably too late but did you happen to notice a coolant loss prior to teardown? any looser than other head bolts? perhaps a head gasket leak?