Low RPM and low top speed RXT260

[surfingboyo]

1tommygunner1927 Here is spark plug photos. The spark tip is not wet and oily, the thread and up is oily.

[surfingboyo]

Front (number three) cylinder with evidence of water. Not sure if it's just water that was in the plug hole and plug got wet when removing.

[1tommygunner1927]

1tommygunner1927 Here is spark plug photos. The spark tip is not wet and oily, the thread and up is oily. Front (number three) cylinder with evidence of water. Not sure if it's just water that was in the plug hole and plug got wet when removing.

I'm still thinking number 3 cylinder has an issue with the spark plug tube seals. What's the history with this ski?

[surfingboyo]

I'm still thinking number 3 cylinder has an issue with the spark plug tube seals. What's the history with this ski?

Yeah I definitely think those seals are leaking. Surely not related to the low rpm slow speed issue though.

I just bought a leak down tester, so I'm going to step through that and see if it points to a head gasket. If there is a leak I'll crack test the head and check the block for warpage.

I bought the ski with a blown head gasket. Had the head machined and valves reseated. Not sure if it ever fixed the issue. Even early on it seemed to be using coolant. I have never had it get hot.

[1tommygunner1927]

Yeah I definitely think those seals are leaking. Surely not related to the low rpm slow speed issue though.

I just bought a leak down tester, so I'm going to step through that and see if it points to a head gasket. If there is a leak I'll crack test the head and check the block for warpage.

I bought the ski with a blown head gasket. Had the head machined and valves reseated. Not sure if it ever fixed the issue. Even early on it seemed to be using coolant. I have never had it get hot.

I think its time to rebuild this engine or replace it with a long block. If you choose to rebuild it, inspect the half-rings/thrust area on the crank, and confirm you have the correct ecu.

[surfingboyo]

Last outing I had a P0122 code that wouldn't clear. Throttle body is new and seems to be moving fine. I thought I'd do the voltage and wiring checks of the tops.

Pin 3 in the tops switch had visible corrosion and with a tiny wiggle broke off. Will order a replacement switch. Any chance a unserviceable pin would be causing the low rpm and top speed issue?

[SplishSplash]

As you had the head off, are you sure of the cam timing? Also, is the knock sensor correctly connected?

[surfingboyo]

As you had the head off, are you sure of the cam timing? Also, is the knock sensor correctly connected?

I took the valve cover off a few weeks ago to check the timing and it was good. I did have a look when I last had the intake manifold off when I inspected it, but I'll verify that when I have it back off to do the leakdown test.

I've ordered a replacement TOPS switch, so will water test it after that and then do the leakdown test after that.

[surfingboyo]

Just did a leakdown test. Wondering what to do next.

Supply pressure is 90psi.

Cyl 3 - 78psi, both exhaust and intake valves (loud bubbling with pressure at oil dip stick)

Cyl 2 - 75psi, both exhaust and intake valves (pressure at dip stick, tiny bit crank locking hole)

Cyl 1 - 30psi, exhaust valve (pressure at crank locking hole)

No visible bubbling in coolant reservoir.

Compression test results:
3 165
2 155
1 145

[John's truck]

I think you have a bad compression tester. Those numbers are too high for a supercharged engine. But, 20 psi difference between cylinders is bad. Especially since that same cylinder failed a leak down test. It’s time for the engine to come apart

[1tommygunner1927]

I've been having issues with a low top speed (103km/hr) and low max revs (7200rpm). Accelerates very slowly in normal mode. Normal key fitted. Ski is a 2014 RXT260X.

Here is a list of replacement parts and testing I have done on it so far:

-new throttle body (TPS reset)
-new intercooler -replaced map and mat sensor
-new spark plug and oil filter
-supercharger just rebuilt
-rebuilt jet pump and pump seal
-solas 15/21 in new condition with no nicks
-new wear ring
-cleaned and tested injectors
-coolant leak test (no leak)
-compression test (strong compression)
-boost leak test (no leak)
-intercooler leak test (no leak)
-no cracks in intake manifold

Anyone with some thoughts on where to go from here?

The video below is not mine, but exact same symptoms as mine.

Well.....are you sure this ski is a RXT-X260? Speed and rpm are more in line with a different model.