MR-1 engine overheating

[84rzv500r]

yep, however there are some other things... I had to make my own shims to set the impeller spacing off the stator housing cause I built Frankenstein pumps... so check the washers under the impellers are installed correctly and fully seated

re: Beatings in housing, I think you put a straight edge across the stator housing without the cone on and measure the depth that'll tell ya if the shaft is pressed all the way

 

[84rzv500r]

Took the port pump apart again and I can’t find anything out of place. I know there is a difference in the impellers and I’m wondering if that is what it is.

I run the same impellers on both sides and I get ~~ 200 RPM less on the STBD side... I think they depitch the trailing side just a degree or two, that said i dont know what stock looks like so its hard to tell if they didn't increase the pitch on the leading edge to give a little more low end bite.

 

[tdonoughue]

Took the port pump apart again and I can’t find anything out of place. I know there is a difference in the impellers and I’m wondering if that is what it is.

Well, it certainly doesn't sound correct...

Sorry if this is a dumb question (have been on hiatus and catching up a bit), but are the engines even? If one of them is 1/16" farther back, then you get that result, right?

 

[84rzv500r]

no this is the impeller housing / impeller set back on the shaft...

the engines are isolated from the driveshaft by the coupler, the light press fit of the driven coupler in the mid bearing is where you can adjust a scosche if need be (or the motor mounts)... im sure there is a spec for the stock setup.. it looks as if it can be only 4 things, impeller size/pitch, thickness of washer behind impeller, stator housing depth, or bearing/shaft location in the stator housing.... even the old AR210/LS2000 shafts are the same spacing on the stator housing...

 

[Brad_Ct]

There is not a lot of space between the impeller and stator. I’m going to run it the way it is and see what happens.

 

[Brad_Ct]

Monday I left a message with tech. support at RIVA Racing about this, yesterday as we were about to launch at the local ramp they called me back. He stated that the impeller should be entirely inside the wear ring so we aborted the launch, returned home and took the pump back off. We disassemble the entire unit and replaced the bearings and seals thinking someone had it apart before and put it back together incorrectly. That turned out to not be the case and we ended up with the same fitment as before.

At this point I was pretty discouraged and took the starboard pump off and disassemble it to compare the two side by side. Every dimension and clearance was the same, I was in the WTF mode until I put the impellers side by side and realized that the difference is the impellers themselves. I knew that the impellers were pitched differently but never thought that would cause the difference.

Reassembled the pumps yesterday and am going to put them back in today and hopefully water test tomorrow.

 

[Brad_Ct]

Made this up today thinking I can plug it into the flush fitting and see what I have for cooling water pressure from the pump.

 

[WREKS]

Took our 2006 SX230 out on the river for the first time since I bought it 4 years ago (ongoing project). I had no water coming out of the front pisser and very little coming from the rear, after running about 5 minutes at 6.5 - 7k rpm the port engine overheated. Thinking I had a plugged hose I pulled the pisser hose off the exhaust elbow and started the engine and got no water.

My Exciter 220 would shoot out of the hole when you hit the throttles but this boat sounds (as my buddy put it) like the clutch is slipping until you get on plane then it will run at 30 mph at 7k rpm with no problem. I pulled the port pump this morning and measured the impeller clearance at .014 which is in spec. the leading edges of the impeller are pretty nicked up though.

Would a nicked up leading edge cause the cavitation and because of the cavitation not enough water is being pushed into the cooling system? It does not overheat on the hose but it also is not running high rpm’s.

I would try to get some cylinder temps along the exhaust side. That may indicate plugged cooling water jackets.

 

[Scottintexas]

View attachment 195142
Made this up today thinking I can plug it into the flush fitting and see what I have for cooling water pressure from the pump.

I'm probably wrong on this,
won't the Y fitting where the flush water meets raw water give bad readings since it would have to backflow or reverse around the Y and give a much less pressure vs. water that is just shooting directly past the Y fitting in a straight line ??

just thinking of the times I remember the flush cap being off, water is not squirting into the cabin like it is coming out the side of the boat,





.

 

[Brad_Ct]

Well today didn’t go well, backed the boat down the ramp and started the port engine. After it warmed up I brought the rpm’s up to 5k and got water out of both pissers but after about 10 minutes the over temp alarm came on again. I measured temps at the exhaust manifold and had 155 degrees on cylinders 1 and 4 and 140 on 2 and 3. I started the starboard engine to compare and the temps were about 10 degrees cooler at the manifold. Starting to think I have a bad temp sensor, I already got permission from my better half to use a pot and HER stove and with a thermometer and ohm meter find out what temperature they are tripping at.

My gauge setup didn’t work, there must be a check valve in the flush line or something.

 

[Brad_Ct]

Did some diagnostics this morning, first I verified that the thermostat was functioning by placing it in a pot of water and at approximately 125 degrees is was fully open. I then started the engine on the hose with my laptop and YDS running to monitor what was going on, engine temp. didn’t go any higher then 158 until I brought the RPMs up to around 4k at that point water temp. increased to around 176 degrees and the engine thermoswitch closed, I verified it was the engine thermoswitch by unplugging it. The manual states that the engine thermoswitch should close between 183 and 194 degrees so it looks like I do not have a sensor problem.

I know this engine was loaded up bad with salt/calcium deposits that I was hoping were removed by doing a acid flush but I’m thinking that the water jackets around the cylinders probably still have some in them.

 

[WREKS]

Did some diagnostics this morning, first I verified that the thermostat was functioning by placing it in a pot of water and at approximately 125 degrees is was fully open. I then started the engine on the hose with my laptop and YDS running to monitor what was going on, engine temp. didn’t go any higher then 158 until I brought the RPMs up to around 4k at that point water temp. increased to around 176 degrees and the engine thermoswitch closed, I verified it was the engine thermoswitch by unplugging it. The manual states that the engine thermoswitch should close between 183 and 194 degrees so it looks like I do not have a sensor problem.

I know this engine was loaded up bad with salt/calcium deposits that I was hoping were removed by doing a acid flush but I’m thinking that the water jackets around the cylinders probably still have some in them.

Problem with MR-1 is that debris has to be flushed upward out of the water jackets through very small holes in the head gasket.

 

[Brad_Ct]

Problem with MR-1 is that debris has to be flushed upward out of the water jackets through very small holes in the head gasket.

That is my understanding of the cooling system on these also, I guess at this point I have no choice but to pull the head off and see what it looks like in there. Trying to decide if I want to do this with the engine in the boat working in the sun and heat or pull the engine and work on it in my air conditioned garage.

 

[WREKS]

It is much easier to work on motor out of boat. It is not a weekend project. It wasn't for me.

 

[Brad_Ct]

Got the exhaust off and found the upper and lower right cooling passages in the head on cylinder #4 plugged up. I opened the top one partially before the picture was taken. Total pain getting the exhaust off with the engine in the boat so the next step is to pull the engine, remove the head and see what is going on.

 

[WREKS]

It is good to check coupler clearance before unbolting from motor mounts in case you need to shim later.

 

[buckbuck]

If I recall correctly the top one does not lead anywhere. It stops just a half inch in. The bottom one is what flows the water.

 

[Brad_Ct]

Built a new gantry this morning since the old one didn’t make the trip when we moved. Hopefully I should have the engine out and apart this weekend.

 

[WREKS]

If I recall correctly the top one does not lead anywhere. It stops just a half inch in. The bottom one is what flows the water. Agreed.
View attachment 195927

 

[Brad_Ct]

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