I never had any problem with the pumps on the 300s. Don't ever remember having to replace one.

 

I have a 1998 explorer just bought throttle assembly is shot ordered new one but I was wondering if should just omit injection pump and run mixed gas???? Your opinion??

 

Pumps on the 250 and 300 engines were reliable,but the 400 pump on account of it's location was a different story.Choice is up to you on blocking the oil injection on the intake manifold and premixing. 40-1 ratio is plenty sufficient.

 

I would rather not omit it but ...but should I??

 

Does injection pump oil anything else crank water pump etc.??

 

Again the choice is yours. If the pump is in good shaped and sealed and not corroded,then use it. Mikuni pumps them were dependable,it's just on the 400 if water got to them and they froze up, engine damage could happen. Injection oil lubricates the upper piston bearing,rings,lower rod bearing, and crank bearings. The counter balancer fluid lubricates the water pump bearing and oil pump gear.

 

What if I ran pump and mixed gas also??? Would it b to much?? And counter balance fluid is 10-30 in crankcase??also my tranny was full of gas I think previous owner put the vaccum spacer if that's what u call it backwards can only blow through it one way comes from tranny to carb I switched it around and drained tranny refilled with Polaris tranny oil haven't run machine yet waiting on my throttle assembly.. If that was backwards would it dump gas into tranny???

 

If the oil pump is working,then premixing the fuel would be too much! Just make sure all vent lines are open,tied up out of the way and not tied to any other vent or drain. Yes if the trans vent was tied into the carb overflow drain it could have gas in it.

 

I have a question my 95 xplorer 400 oil pump return spring is not working when I give throttle not running the pump opens full and doesn't return also turning by hand does not return is there a way to repair the spring or replace or put another spring somewhere else .

 

I normally bypass oil pumps when they get some age on them and just premix oil with fuel if pump stops working while riding atv could damage piston and cylinder I think alot of 2cycles atv are setup to use 1 to 1 ratio 1 tank of oil to 1 tank of fuel as atv get older the pump start getting wear and the ratio changes less and less before you know atv does not have any power cause piston and cylinder damage I have not ever repaired 1 of them pumps