Possible bad SBT motor

[94spx]

I posted to oil in bilge but wanted to get some attention. I have a SBT motor with 10 hours on it. The #1 cylinder seems to be getting oil in while sitting. Does the oil pump have a check valve that may be stuck? It could be going into #1 from there because of the angle of the machine on the trailer(foward).

[John Kubiak]

what model engine? Some have check valves and they can and do fail.

[94spx]

It's a 720.

[John Kubiak]

Then it is quite possible that the check valves located in the banjo fittings on the oil pump are bad. I would definitely check those first, they are not very expensive, and could save you an unnecessary engine replacement.

[94spx]

Well lets think about this......if I'm going to all that effort and I have a block off kit, should I just switch to premix?

[John Kubiak]

Sure let's think about it.

Repair oil fitting banjo

Parts $15.00. time

Time 1/2 hour

Replace oil pump with block off

Parts Block off $15.00
Intake gasket set $10.50

Time 1-1/2 to 2 hours

Retain your oil injection system if at all possible. Variable rate oil injection adds less environmental issues to each and every PWC.

Pre-Mix is normally mixed for wide-open-throttle and is way too rich for average riding, and results in excessive smoke and poor running conditions.

Forget to mix oil in the gas just once, and all of those savings just burnt up.

[94spx]

Is the banjo you're referring to where the oil lines connect to the pump? I guess the real question here what am I looking doing to check the for the problem? Am I taking out the oil pump assembly? Are you thinking it's the valve assembly itself that's leaking past?

[raider1100]

Nope most likley is a bad crank seal between the #1 cylinder and the rotary valve oil bath. call bryan
Rob

[94spx]

Hello?

[Bryan Glynn]

He's saying replace the check valve and see if it cures it before going pre-mix.

[94spx]

Thanx Bryan, is the check valve in the pump assembly, thus requiring the assembly to be removed?

[94spx]

Just looked it up in the manual and got my answer-thanks. I started taking it apart tonight and found blue form a gasket around the oil pump base. Coincidentally, I also found a lot of oil there to-hmmmm. So if the pump is not sealed, then is gravity taking over and letting the oil flow thru the feed lines?

[94spx]

Need an opinion here....first how do I get the dang oil pump gear off the shaft w/o breaking it? Second, i'm a little leary of the existing oil pump... it was installed w/o a gasket/o-ring and I noticed 1 screw missing from the diapram cover-another source of leakage. Do I rebuild still and assume the rest is ok or premix?

[Bill O'Neal]

First off, the oil pump does not have a gasket, only a small oring.
Remove all 4 small screws in the cover and put red loc-tite on them and re-install them. The one that fell out is in the bilge.

I don't know why you want to remove the plastic gear, unless there is a need to remove the manifold from the RV cover, but after removing the nut and washer, it prys right off.

[94spx]

I need to remove the gear to put an o-ring on for the pump....there is nothing there,,, are you saying a little form-a gasket is ok to use as a substitute?