MR-1 engine overheating

[Brad_Ct]

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.

 

[Brad_Ct]

Also should the transition from the glass to the aluminum be smoother then what I have in the second picture?

 

[Scottintexas]

does it piss water running on the hose ??
that would be my first route, blocked hose somewhere ?
on the hose block off your cooling water inlet to the rear of the 'Y' fitting to force all water into the engine,


dings could cause a resulting low cooling flow,
on the water,
I might disconnect the hose before it enters the 'y" fitting to make sure they're are no clogs or restrictions and water is shooting out,

I might even idle or slightly increase rpms to see if it's increasing flow, then I might reconnect and then disconnect the pisser line at the engine to see if it's doing it there,


knowing the sorted history of this boat I wouldn't rule out anything,

transition issue is very subjective, it could certainly be causing the jet to "slip"

https://jetboaters.net/threads/cavitation-missing-sealant-in-pump-grate-fixed.884/

Do you know you have the correct impellers installed on each side ??

 

[Scottintexas]

the dings in the picture are nothing compared to what my impellers looked like and I only lost about 5mph top end,

 

[Scottintexas]

did you pull the screen on the jet pump intake to make sure it was clean ??



.

 

[Brad_Ct]

does it piss water running on the hose ??
that would be my first route, blocked hose somewhere ?
on the hose block off your cooling water inlet to the rear of the 'Y' fitting to force all water into the engine,


dings could cause a resulting low cooling flow,
on the water,
I might disconnect the hose before it enters the 'y" fitting to make sure they're are no clogs or restrictions and water is shooting out,

I might even idle or slightly increase rpms to see if it's increasing flow, then I might reconnect and then disconnect the pisser line at the engine to see if it's doing it there,


knowing the sorted history of this boat I wouldn't rule out anything,

transition issue is very subjective, it could certainly be causing the jet to "slip"

https://jetboaters.net/threads/cavitation-missing-sealant-in-pump-grate-fixed.884/

Do you know you have the correct impellers installed on each side ??

I do not have any water coming out the pissers on either engine on the hose. I removed on of the hoses from the 3 way splitter to the exhaust while we were on the water with the engine off and water was pouring out so I don’t think there are any blockages in the hose from the pump. Impellers are on the correct sides. I ordered new impellers and am going to smooth out the transitions in the tunnels.

 

[Brad_Ct]

did you pull the screen on the jet pump intake to make sure it was clean ??



.

Yes I did

 

[Scottintexas]

here is buckbuck's picture with the thermal camera,
I don't think I'd necessarily trust the sensors at this point, use a IR thermometer to at least compare spots on the good engine to help identify where the overheat area is,

https://jetboaters.net/threads/engine-over-heat-after-tow-rope-caught.22653/post-384135

if it's not in your lines,
a cheap trouble shooting could be to cross your cooling water linet lines at the "y" fitting to see if the problem follows the intake line (jet pump), you could at least narrow it down to maybe it is the impeller,

If it's not the impeller and your lines are clear that just leaves deposits in your engine and exhaust pipe,

you might at least disconnect the exhaust pipe to see the condition of the cooling passages, that may be easier than removing the exhaust manifold, your cooling water goes directly to it along with your engine,



and you've seen this I'm sure,

.

 

[Brad_Ct]

This engine has been a issue from the beginning, it originally overheated running on the hose until I did a modified crankygipsey flush and cleaned up the bypass valve in the cooling system. I have also replaced the exhaust elbow and pipe because it was very corroded at the sealing surfaces after I determined a bad seal was causing water in the oil.

 

[Scottintexas]

I think I would swap the inbound cooling lines, that would be a cheap/easy way to see if it was the input side of the engine,

cavitation is such a hard problem, it can be the silicone or the impeller ding or a little of both, and how much is enough to cause the problem ????

 

[Brad_Ct]

Both pumps have cavitation but the starboard engine was replaced with one out of a fresh water jetski. My thought is that the port engine still has some crap built up in it. Tomorrow I’m going to pull the anode and bypass valve and see what they look like, also going to pull back the boot on the exhaust elbow and see if the cooling passages are plugged up.

 

[Brad_Ct]

Pulled everything apart and found no signs of blockage anywhere. Going to run it on the hose tomorrow with the cooling line from the pump crimped to make sure I have water coming out the exhaust and pissers.

New impellers arrived this morning, ordered them from Partzilla around noon yesterday and they were delivered at 11:30 this morning.

 

[84rzv500r]

good plan.... the $64,000 question is what do you have coming out the pissers at say 7000 on plane?... I dump all the cooling water out the starboard side so I can keep an eye on it... with the exception of the last exhaust outlet that dumps back into the exhaust after the waterbox at the exhaust through hull elbow...

the exhaust collector pisser usually only flows steady above like 5-6000 on my set up.

I have heard of flashing sniglets in distribution tee getting clogged up...

put a pair of vice grips on the hose back to the pump screen whilst on the hose and see if you don't get a little more out the pissers?
you can also clamp off the hose big hose going from the tstat to the transom plate and push more water through the pissers and see if that dont clear it up...

 

[Brad_Ct]

good plan.... the $64,000 question is what do you have coming out the pissers at say 7000 on plane?... I dump all the cooling water out the starboard side so I can keep an eye on it... with the exception of the last exhaust outlet that dumps back into the exhaust after the waterbox at the exhaust through hull elbow...

the exhaust collector pisser usually only flows steady above like 5-6000 on my set up.

I have heard of flashing sniglets in distribution tee getting clogged up...

put a pair of vice grips on the hose back to the pump screen whilst on the hose and see if you don't get a little more out the pissers?
you can also clamp off the hose big hose going from the tstat to the transom plate and push more water through the pissers and see if that dont clear it up...

I didn’t see any water coming from the front pisser and very little from the rear one at high RPMs. Water was streaming out on the starboard engine.

 

[84rzv500r]

hmmm as you say cavitation will reduce the coolant output... but im betting on a blockage or a collapsed hose

 

[Brad_Ct]

I just ran it on the hose with the supply from the pump crimped at first and I had water coming out the exhaust, the line of the bottom of the thermostat, and the rear pisser. I then crimped the line off the bottom of the thermostat and got water out the front pisser, not a lot but enough to verify flow. Ran it for probably 15 minutes and the engine didn’t overheat.

I’m going to silicon up all the transitions in the tunnels and replace the impellers and see what happens.

 

[tdonoughue]

(not addressing the overheating problem, but I would run some trimmer line down the front pisser, probably while on the hose like you had it to flush the crap out. sounds like you might still have something in there.)

 

[Brad_Ct]

(not addressing the overheating problem, but I would run some trimmer line down the front pisser, probably while on the hose like you had it to flush the crap out. sounds like you might still have something in there.)

I took the front hose off the exhaust boot and blew it out with compressed air and it’s clear.

 

[Brad_Ct]

I got the new impellers on and for some reason the leading edge is approximately 1/16” forward of the wear ring on the port side, the starboard is is further back and not sticking out like this.

I measured from the end of the impellers to the end of the shafts and it’s the same, but measuring from surface of the wear ring the end of shaft and it appears that the port is around 1/16” longer.

Only way I can see this happening is if the shaft is not pressed all the way into the cone bearings.

Does that sound correct?

 

[Brad_Ct]

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.