2005 Yamaha SX230 Project

[19samson77]

Hello All,

Last September I picked up a pretty clean 2005 SX230 at a really fair price. It is my first boat but I expected issues. I am mechanically inclined and play with cars, bikes and still love my big chainsaws. Anyway, we took it out a few times and on the second trip the starboard engine would get a low oil pressure warning after running full out and backing off. (I should mention the oil was overfilled when I got it and it did the puke into the air box thing, so I got that sorted and put in new filters.) Then on the next trip out to troubleshoot the starboard engine, the port engine started to misfire and I could smell gas. Got it home and was going to change the plugs as they had come in and found water in the middle two cylinders. Yes water not fuel and not enough to lock the engine but enough to foul the plugs. So I cranked on it until the cylinders were clear, put the plugs in and started it up for three, 30 second runs, five minutes apart to dry everything out.

By then it was getting cold (I am in upstate NY) so I figured I would put the boat away and deal with it in the spring. It is stored in an old anchor store at the mall that keeps it at 62 degrees so no worry about extreme cold. So it has been a few months now and planning my attack. I am guessing an oil pump or internal filters on the one and a head gasket on the other.

A couple weeks ago I picked up a spare engine complete with intake and exhaust with the oil pump. Figured worst case I get an oil pump, cooler and maybe head and block. The guy had been through it but seemed to know what he was talking about. It had been getting water in the oil and after the second pull he found a ski engine and swapped it in. He seemed to think the chips in the exhaust manifold were letting the oil in but I have my doubts. I would like to get this engine cleaned up but want to see if there is an internal crack in the block before I waste too much time. The head is off so a pressure test would be a PITA. Any ideas???

So when the boat comes out of storage we are pulling both engines and doing what we gotta do. Should be an adventure but my son and I are going through the spare engine first to get familiar with this motor. Would just be nice if we just had one ready to drop in. That way we just have to get one of the two engines in it fight to fight before we could play with the boat.

Regards, Ethan

 

[19samson77]

You can see the chips in the manifold on the first picture. If there is a crack in the block it must be internal.

 

[Cobra Jet Steering LLC]

check around the water jackets on the exhaust manifold for corrosion that will let water leak in to the middle cylinders

 

[Beachbummer]

That section looks very suspicious.

 

[WREKS]

JB weld?

 

[19samson77]

There are chips for sure and I can see the water getting in the cylinder but how would it get in the oil. Yes it can seep around the rings or maybe get through a valve guide but not while running. Either way that manifold is getting welded up next week. Older guy who is good with aluminum Not me.

 

[Cobra Jet Steering LLC]

Be sure to resurface all the parts before you put it back together , Use a big thick piece of glass and some sand paper glued to it remove all the dark spots on the mating surfaces.

 

[WREKS]

Check 'Milky OIl Repair' post #1. I had water/steam getting into cylinder 1 from a nearby cooling water passageway.

 

[19samson77]

Any thoughts on the SBT rebuild kits? The gasket set is a must but are they good?

 

[19samson77]

FYSA I am stuck here with COVID so lots of time to plan and still floored enough to not be in the garage. Finally got me…I will be fine though already perking up.

 

[19samson77]

All told I still think it is a good engine for $600. Just looking now I am thinking the water return out of the valve cover looks suspect. A few more pictures as well.

 

[19samson77]

I like the glass and sandpaper idea.

 

[WREKS]

Had the heads off each engine at least three times each. Haven't replaced a head gasket yet. Just spray paint them and reuse them. Haven't had one leak yet.

 

[Cobra Jet Steering LLC]

It's nothing new , people did that to smooth out the surfaces of the head, and manifolds before putting parts back together so they knew the parts were cut smooth. I actually built a machine to do it because it was a standard thing to do and pushing parts across a flat surface was time consuming and a pain in the neck. I would always use new gaskets and I purchased a lot from S B T with no issues.

 

[WREKS]

I just replace the o-ring on the cooling water return pipe, but it has never leaked, any way.

 

[WREKS]

Forgot-I treat all mating surfaces with Permatex Aviation Form-A-Gasket Sealant Liquid. Admittingly, I do not put a lot of hours on them, but have run in the 7-8 k range long enough for a problem to surface.

 

[Cobra Jet Steering LLC]

it's your boat do it your way But I would not do it that way on mine.

 

[WREKS]

I wouldn't either if the prices were reasonable, but they are not. The two and three layer stainless gaskets do not deform, so i have no issue reusing them. Try measuring one with a micrometer sometime before and after and see if you can tell the difference. However, torquing the head requires some care. One member here replaced the head bolts fearing the bolts may stretch a bit. I just reuse just about everything i can.

 

[19samson77]

In this case I have to replace the head gasket as it has some pretty bad bends in it. The nuts to tighten the head are missing too so I am getting an order together. Best I can tell so far is that the MR1 is a rock solid engine with an over complicated cooling and exhaust system. Oiling could be simplified as well but I get the origin.

 

[kjr6306]

Any update on your engine project? Did you ever figure out how the water was getting in the oil?