Need help with yamaha 2013 sx240 oil pressure ?

[Brandon neidemire]

Hello
I got an sbt engine last year with 45 hrs on it. I know a real mistake. I tried to get 2 for my boat but they couldn't get me another good one last year so I built one from yamaha. But the sbt 1.8 ho all of the sudden popped a low oil pressure light . Runs 7400 rpm never misses a beat. Tested the oil pressure switch and it's good. Pulled the pump and there is some scarring on it but not gouging. Looks as if it should pump ok. Took compressed air and pulled pressure switch out and blew through engine. Reinstalled pump new oil filter and it went to 60 psi. As it warmed up it dropped to 21 on idle and 40 on full throttle. SBT IS A JOKE . I'm thinking bad tolerances on bearings. The warmer it gets the lower the oil drops. Anyone have another idea I might be missing ?

 

[WREKS]

Did you ever have that problem on the old engine>

 

[Brandon neidemire]

I don't know for sure. When I bought the boat I replaced both engines. One was hammering and the other ran fine but had tons of scarring in the cylinders. Someone didn't take good care of it. I should of just bit the bullet and bought a new one.

 

[Brandon neidemire]

I had the local yamaha dealer go through the oil cooler and had a brand new pump on it.

 

[cybuch]

Yep having the same issue with SBT and the MR1 motor, exact same problem. This is the second time I am shipping it back for low oil pressure, I have a 2 year warranty, not that it helps since its at SBT more than on the water. I think you are correct on the tolerances. If this doesn't work, I am going to ask for a refund and I am going to drop two 1.8s in my 2005 AR230

 

[WREKS]

Correct me if I am wrong but, I think the oil pressure is determined by the feed pump part of the oil pump. That is not part of the SBT package.

 

[cybuch]

Correct, but he said he put in a brand new oil pump, as did I. If the bearings are out of tolerance it would cause blow by and the oil pressure would drop

 

[Brandon neidemire]

So I took off the pump and it did have some scarring in it( new 45-50 hrs on it) cleaned out and blew air through the oil passage hole that the oil sending switch is screwed into. New oil, started it up, 60 psi. The longer I ran it the lower the oil pressure. I pulled out the oil and replaced it with straight 30 weight. 20 psi at idle. 38-40 full throttle.

 

[WREKS]

Correct me again! I see no bearings in the Oil Pump itself, just a shaft that is driven by the Oil Pump Drive Shaft which is inside the Reduction Gear Box. If the of end that shaft is worn out and not coupling properly with the Oil Pump Shaft, it should be visible when the Oil Pump is removed.

 

[Brandon neidemire]

From what I have been able to determine through extensive research is that the hotter the engine gets the looser it is the less the oil pressure. I believe that sbt is polishing cranks or turning them down and not replacing the bearing with oversized. Last year they sent me an engine and it made all kinds of noise. We got permission from SBT to take the head cover off. All the valves we're out of clearance and needed reshimmed. They sent me another head and we installed and the cams were grinding themselves into the head and producing shavings. That's when we sent the engine and a head back and got money back. Not without a fight though! I built a yamaha for that side and called it a day. Wasted whole summer!

 

[Brandon neidemire]

So yes no visible bearings. Possibly a bushing in the pump. A gear coming out of the pump that mates with the gear on the end of the crankshaft . That looks good. Possibly the crank has some wobble not mating well to the oil pump gear causing skipping ?

 

[Brandon neidemire]

So at this point I am going to cut my losses here. I have no faith that SBT can correct the problem ! I just ordered a new head, block, oil pump , cam tensioner , oil pipe , and full gasket kit. All will be here next week except the damn block . It's backordered till july 23. Anyone who wants to buy the engine with 45-50 hrs on it let me know. I would be willing to also leave the head cover on it and the new owner could send it to sbt for fixing or replacing as it has about another year warranty on it. It currently runs like a top at 7400 rpm.it currently will be in the boat until block comes in if someone can come up with a fix ?

 

[WREKS]

Can you post a picture of the Reduction Gear Box without the Oil Pump attached?

 

[WREKS]

@Brandon neidemire From what you and @cybuch are describing, the problem may be inside the Reduction Gear Box.

 

[Brandon neidemire]

What are we considering as a reduction gear box ? Does the pump just bolt to the back of the block and the gear coming off the pump mate up to the gear on the crankshaft ? Or am I missing something else ?

 

[Brandon neidemire]

I just ordered a service manual online I will check that out. I currently have the pump in but wouldn't be opposed to taking it off and getting a pic of the back of the crank and block

 

[Brandon neidemire]

Looks like the pump just runs off the crank gear that bolts over the crank ? Correct ? Would it be a possibility that the gear that slips over the crank doesn't have a bolt holding it on ? I would have to remove the pump to double check.

 

[Brandon neidemire]

Here is the breakdown

 

[WREKS]

@Brandon neidemire Sorry! I'm confusing your oil pump with the MR-1 engine oil pump, I would still try to examine the oil pump once you have the engine removed.

 

[Brandon neidemire]

Hey no prob. I will take any interest in helping me out. Thank you