New 295 Rebuild wont run

[dczrboy]

I think your right. I used the original ring on the oil pump cover because the aftermarket one was too thick in my opinion and did not let the cover sit flush. I put the small oring in under the cover but I remember it not fitting in the groove very good so I was very careful putting the cover back on but I guess the oring could have moved because like you said something is going on to not have the oil pump to the top.

[CP241]

The aftermarket o rings for the oil pump and the engine side cover NEVER fit right. I’ve had much better results reusing the old oem ones.

Welcome to the land of the MCI. I truly feel your pain. I had a workhorse fight me big time. I had to have removed that motor at least a dozen times or more. I learned a lot from that cart and the next few were a lot smoother but, I learned, just my opinion but I try to avoid those motors. They’re just designed for lubrications failure. The pre mci motors are much much better

[dczrboy]

Thanks for the info. Looks like I’m going to get to tear it out again too!

[slonomo]

Originally Posted by CP241

I think you’ve found your problem. It’s shooting oil out the breather because it’s “overfilled”. And
By “overfilled” I mean it’s got too much oil in the bottom end because it’s not making it to the head.

That's what I was thinking. Good call.

[jwalsh965]

I here your pain, i just rebuilt a same engine. I have tried everything to get it to pump oil but with little success. The new o-ring was larger and i put old one back in, i primed the pump, still wont pump. i blew out all the oil ports nothing was blocked. Next i will take apart that valve under carb, because i might have assembled it wrong. after rebuilding the engine i can't get cart to fire up, no spark so i am battling 2 demons and also wondering does engine create enough oil pressure by just turning engine over. i will follow your post and if i figure it out i will post it.

[CP241]

That’s the issue I have with these. There are so many potential failure points in the lubrication system. Minor minor failures create catastrophic failures downstream.

Trig or someone can chime in if I miss something but off the top of my head...
o ring on oil pump cover
Oil pump cover not flat
O ring above oil pump going into the case
Seal from oil filter/pickup to oil pump
Oil pressure relief check ball/spring
Excessive clearance between pump and cover


Or in the case of one of my nightmares, a pin hole in the engine cover behind the oil pump itself. Still not sure how that happened.

Any slight leakage anywhere in the system will create pressure loss. It’s extra sensitive on these motors because for some reason they put the pump halfway up the motor instead of in the sump. So it has to suck oil up to the pump, and then pump it from there. The sucking oil up from the sump is not very efficient and I think that’s where the issues come from.

[JPonLKN]

Originally Posted by jwalsh965

I here your pain, i just rebuilt a same engine. I have tried everything to get it to pump oil but with little success. The new o-ring was larger and i put old one back in, i primed the pump, still wont pump. i blew out all the oil ports nothing was blocked. Next i will take apart that valve under carb, because i might have assembled it wrong. after rebuilding the engine i can't get cart to fire up, no spark so i am battling 2 demons and also wondering does engine create enough oil pressure by just turning engine over. i will follow your post and if i figure it out i will post it.

I thought I was fighting the oil pressure issue at one point on one of my MPT's, turns out, I had a bad oil check valve in the oil pressure sensor passage. Would not let oil in that passage to the sensor. If you remove the oil cap on the valve cover, and you turn over the engine, it will take a few rotations, but it will pump oil and spay it across the top of the cam, provided you have oil pressure. I don't think you can hurt it turning it over without firing, but I wouldn't run the engine unless you know you have oil at the head.
As for no spark, if it was running before you took it apart, it is likely a wiring issue, or a ground issue. Make sure every wire is where it belongs at the solenoid, ignitor, etc. These connectors can appear to be good, but not make positive connections, causing these "no spark" symptoms.
In the future, if you are looking for help on your cart, start your own separate thread. It prevents confusion for those trying to help go through what has been done/suggested, etc.