MR-1 engine overheating

[Scottintexas]

At least you know what your dealing with and you don't have any corrosion going into the cylinder wall that we've seen before

 

[Brad_Ct]

At least you know what your dealing with and you don't have any corrosion going into the cylinder wall that we've seen before

Yes as far as the internals of the engine it looks ok. This engine was seized also when I bought the boat but I was able to free it up, both compression and leak down tests showed there is some wear but it’s not terrible.

The question now is how do I get it all out? Last thing I want is to have this stuff floating around in the cooling system plugging passages up again.

I’m almost to the point of pulling the plug and just buy another engine. I have been searching for used skis but it seems to be harder to find non HO engines. I have found two used complete engines, one is $3k and the other they want $5k for with no guarantee and I won’t be able to test run them. The only other choice would be a SBT engine, I know people slam them all the time but I can’t imagine a company being in business as long as they have been and selling all junk engines. The other plus is that it would have a guarantee and they are only a couple hour drive away.

 

[WREKS]

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It’s not pretty, #4 jacket plugged solid along with a lot of the passages in the head.

Nice work. I believe that stuff is a dried microbial buildup similar to that which the ac guys suck out of plugged condensate drains. After, having similar experiences to yours ( yes, more than one ), I started dry-firing the motors a few days after flushing for periods of about 60 wake-mode flashes to evaporate all the residual water out of the cooling system. I have not had an overheating problem since I started using this procedure..

 

[Brad_Ct]

Nice work. I believe that stuff is a dried microbial buildup similar to that which the ac guys suck out of plugged condensate drains. After, having similar experiences to yours ( yes, more than one ), I started dry-firing the motors a few days after flushing for periods of about 60 wake-mode flashes to evaporate all the residual water out of the cooling system. I have not had an overheating problem since I started using this procedure..

I don’t know what this stuff actually is but to me it has the characteristics of salt. I agree with you on drying the engine and exhaust out afterwards, a lot of people say these engines are self draining but I was surprised at how much water came out of the exhaust, oil cooler, and lines when I disconnected them.

 

[tdonoughue]

So now that you have a chunk of the stuff, you can try soaking that in vinegar or CLR or Salt Away to see what might eat it best without eating the block...

 

[Brad_Ct]

So now that you have a chunk of the stuff, you can try soaking that in vinegar or CLR or Salt Away to see what might eat it best without eating the block...

That is probably what I am going to do, at the top of the jacket it was hard but the further down I went it was wet with a doughy consistency.

As I stated above I’m concerned about not getting it all out and then having it plug up the smaller passages.

 

[tdonoughue]

Yep. That is why finding out what will chemically eat it will be your best course. Only thing that will get everywhere and remove it will be a liquid...

 

[WREKS]

I don’t know what this stuff actually is but to me it has the characteristics of salt. I agree with you on drying the engine and exhaust out afterwards, a lot of people say these engines are self draining but I was surprised at how much water came out of the exhaust, oil cooler, and lines when I disconnected them.

They are self draining but not self drying. Just like an ac condensate line, the engine stays wet inside unless it is dried out. We know: Where there is water, there is life. You may have noticed some jelly-siliconey looking stuff. That is what it looks like before it starts drying out becoming like the piece you are holding

 

[Brad_Ct]

I’m calling SBT tomorrow about getting an engine from them. I’ll clean this one up, put it back together and save it for backup.

 

[Brad_Ct]

I took a closer look at this engine today and I’m surprised I had as high of compression readings as I had. As you can see #2 cylinder is badly rusted, waiting on a puller so I can get the flywheel off and I am going to order a SBT engine.

 

[WREKS]

View attachment 196092
I took a closer look at this engine today and I’m surprised I had as high of compression readings as I had. As you can see #2 cylinder is badly rusted, waiting on a puller so I can get the flywheel off and I am going to order a SBT engine.

If you had milky oil, the second cylinder may have been the source. I had small corrosion canal in the head that allowed cooling water to get into the cylinder.

 

[Brad_Ct]

If you had milky oil, the second cylinder may have been the source. I had small corrosion canal in the head that allowed cooling water to get into the cylinder.

Both the engines were seized when I boat this boat, this one I was able to free up and get running. I’m pretty sure that is where the rust came from.

I still have the other engine that I disassembled with two pistons still rusted into the cylinders. I talked to SBT this afternoon and confirmed with them what was considered a good core and that engine meets their criteria so that is the one they are getting.

 

[WREKS]

Yep. That is why finding out what will chemically eat it will be your best course. Only thing that will get everywhere and remove it will be a liquid...

There is no fluid better and cheaper than hot dry air. As the saying goes, "An ounce of prevention...."

 

[Brad_Ct]

Puller came in the mail this morning so I pulled off the flywheel and ordered an engine. Very friendly and knowledgeable over the phone.

 

[84rzv500r]

Ive had good luck with SBT.... I bought 3 1200 triples, a 4-TEC 155, and 2 MR-1 HO's, and numerous other parts. the only products i had issue with are the drive shafts... i've broken 2 of the 20mm SBT shafts as I've posted before. Granted I was hard on them...

 

[Brad_Ct]

That’s good to know, seems like all you hear about them is when people have issues. Like I posted earlier, they have been in business a long time and they wouldn’t have been if they sold all bad engines.

 

[tdonoughue]

The percentage of people posting gripes is always far greater than the percentage posting of their positive experience. Universal truth.

 

[Brad_Ct]

Got a call from SBT this morning saying the engine is ready, so a road trip to Clearwater tomorrow is on my agenda.

 

[Brad_Ct]

It sure is pretty, so far I am very impressed with them. Everyone I have dealt with have been very pleasant and knowledgeable, their showroom is very nice. Picked up a gallon of Yamalube and two oil filters while there, oil was $27 a gallon and filters were $9 and change.

 

[Brad_Ct]

Friend of ours came up from Marco around 9 this morning to help me put the engine in. Had it in and running by 11:30 and in the water at 12:45. Ran from the Franklin Locks up to Labelle for lunch and back, 3 hrs. total run time and it runs great.