Carbon build up

[Boyd12]

My 951 engine has .8 hours on it over the last few weeks after rebuild. I have only been running it on the trailer at idle and revving it up, to get it set up. I havent ridden it yet. I looked and the pistons are clean, NO carbon at all. I see no evidence of water in it. My question is how long until deposits begin to show up?
With my 03 Di, it had some carbon deposits showing at 2 hours.
Also, I have 50:1 in the fuel and the oil pump is set slightly rich.

 

[mikidymac]

You should never be breaking it in on the trailer, with no load on the engine you are doing more harm than good because the rings will never seat without a load.

You may have already ruined your driveshaft seal from no cooling water.

Never premix a Direct Injected ski as it can ruin the fuel injectors.

 

[Boyd12]

You should never be breaking it in on the trailer, with no load on the engine you are doing more harm than good because the rings will never seat without a load.

You may have already ruined your driveshaft seal from no cooling water.

Never premix a Direct Injected ski as it can ruin the fuel injectors.

Apologies, my post was not clear at all!
I take it to the lake, leave it on the trailer and run it in the water. That is what I meant by running it on the trailer.
This ski is carbed so no premix
Thank you!

 

[mikidymac]

Ok, yes, premix is good on the carbed skis for the first tank.
I would really suggest getting it out and riding it to vary the throttle and load the engine better than just with the trailer backed into the water.

 

[Boyd12]

The exhaust pipe gets hot, the engine stays cool. as soon as I have time pursue/fix the issue I will ride it. I would REALLY like to go riding!

 

[etemplet]

If your exhaust pipe is getting how you're not flowing enough cooling water through it. Do you by any chance have a quick connect hose fitting on the line we use flush the skis from the rear? There was one on a 2003 DI and I got a high engine temp warning after about 5 minutes of riding. I remembered seeing that fitting so I removed it and all was well.

On the hot exhaust, remove the hoses and blow through them and through the fittings. I find lots of those are plugged with dirt. Check your Water Control Valve. Good Luck !!

 

[Boyd12]

If your exhaust pipe is getting how you're not flowing enough cooling water through it. Do you by any chance have a quick connect hose fitting on the line we use flush the skis from the rear? There was one on a 2003 DI and I got a high engine temp warning after about 5 minutes of riding. I remembered seeing that fitting so I removed it and all was well.

On the hot exhaust, remove the hoses and blow through them and through the fittings. I find lots of those are plugged with dirt. Check your Water Control Valve. Good Luck !!

It is a 99 XP 947 that I picked up recently. The engine was exploded by the previous owner so I rebuilt it. Many parts were missing.
The engine runs well, but the issue is
1. the tuned pipe gets very hot after a couple minutes of operation and
2. no water exits on the left side of the hull.
The cylinder and head geta warm, not hot, which is good.
The pressure regulator on the muffler leaked, so I replaced it with a used one. No leaks.
I blew out all of the coolant lines during the process and the engine passed the leak down tests. There is no evidence of water in the combustion chambers.
According to the SD shop manual, most of the water to the tuned pipe comes from the pump, through the head/cylinder and exhaust manifold, then to the pipe. If the engine is cool, then it is getting water. SOME water is directed by the pressure regulator, but very little compared to what comes through the head/engine, so it would seem most of the cooling is done by water coming from the pump.
I tested it using the SD hose adapter which runs the water backwards, so it gets to the pipe first. The pipe was cool.
I made a fitting to insert in the water inlet where the pump bolts to the hull so water would go the way it does when the hull is in the water; results were engine and pipe were cool. Lake test was same as usual, pipe hot, engine cool.
I just found the oring that fits between the pump and the hull was missing. see photo. Could that oring cause the system to work well enough to cool the engine but well enough to cool the pipe?
Also, I have a bronze pump and a plastic one. The holes on the plastic pump are larger. I doubt that would effect anything, but...
Your thoughts?
Thank you!

 

[mikidymac]

Yes you need the o-ring. Even a worn wear ring can cause overheating due to low cooling flow.

 

[etemplet]

I'd look at the fittings for plugging and the water control valve you installed may not be the proper ones. There are numbers on the fittings (elbows and such) and the internal diameters are different. That may be a restriction for your engine cooling water flow. I have a lot of 951 exhausts system parts so if you need me to check anything for your just ask. I've noticed different springs on the valves. You should have copious amounts of water flowing out of the exhaust. I'd buy a $30 infra red thermometer and check the difference in the temperatures when the ski is running and at speed. Perhaps you have a bad rubber hose on the exhaust. I've seen melted rubber connectors on RFI exhaust systems. If it's hot it's not getting water.

Those two lines close to one another are siphons to remove the bilge water. Are you sure your jet pump doesn't have any restrictions in the suction line? You can blow air back through it. I'd blow air through everything.

Is there a chance you have to two hoses coming out if the right side of the engine swapped?? One is up high and goes to the exhaust. The other is down low and goes to the drain.

I have a 1999XPL that has been sitting for a couple of years. The engine is out and in the shop. I was just not sure how much fun the ski would be. LOL Good Luck !!

Let us know how you make out.

 

[Boyd12]

Yes you need the o-ring. Even a worn wear ring can cause overheating due to low cooling flow.

The o-ring fixed it! YAY!

 

[Boyd12]

I'd look at the fittings for plugging and the water control valve you installed may not be the proper ones. There are numbers on the fittings (elbows and such) and the internal diameters are different. That may be a restriction for your engine cooling water flow. I have a lot of 951 exhausts system parts so if you need me to check anything for your just ask. I've noticed different springs on the valves. You should have copious amounts of water flowing out of the exhaust. I'd buy a $30 infra red thermometer and check the difference in the temperatures when the ski is running and at speed. Perhaps you have a bad rubber hose on the exhaust. I've seen melted rubber connectors on RFI exhaust systems. If it's hot it's not getting water.

Those two lines close to one another are siphons to remove the bilge water. Are you sure your jet pump doesn't have any restrictions in the suction line? You can blow air back through it. I'd blow air through everything.

Is there a chance you have to two hoses coming out if the right side of the engine swapped?? One is up high and goes to the exhaust. The other is down low and goes to the drain.

I have a 1999XPL that has been sitting for a couple of years. The engine is out and in the shop. I was just not sure how much fun the ski would be. LOL Good Luck !!

Let us know how you make out.

Thank for your help! I wish I lived closer! I replaced the o-ring and it fixed it. I have other issues, but now I get to move forward. I am going to get an infra red thermometer. That is a good idea!

 

[mikidymac]

Awesome!!!

 

[etemplet]

Good news Indeed !!