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Engine misses after sitting in storage all summer?

Turboflash

Turboflash

TY 4 Stroke God
Joined
Mar 18, 2019
Messages
2,446
Location
Southern MN
Country
USA
Snowmobile
'17 ZR9000 Ltd. 137 - PEFI Stage 4
Just wondering if anyone has experienced a situation where a 998 has been sitting in storage all summer (since April) and when you go to crank it now (Nov) there seems to be no compression, ie motor "skips" when cranked, like 1 or more cylinders has no compression? Once started, motor seems to run normally. Sled has about 3500 miles on it. Sled was stored with ethanol-free gas with prescribed amount of Seafoam and a tiny bit of 2S oil in gas. Why does it crank like 1 cylinder is low on compression?
 

Run it for a few times over a week it will probably be back to normal.


It what mine was like!
 
stgdz said:
Run it for a few times over a week it will probably be back to normal.


It what mine was like!
Click to expand...
I had an RX-1 do that years ago. It was like the lifters discharged. The engine cranked like it had no compression. Once started it was normal thereafter.
 
Turboflash said:
Just wondering if anyone has experienced a situation where a 998 has been sitting in storage all summer (since April) and when you go to crank it now (Nov) there seems to be no compression, ie motor "skips" when cranked, like 1 or more cylinders has no compression? Once started, motor seems to run normally. Sled has about 3500 miles on it. Sled was stored with ethanol-free gas with prescribed amount of Seafoam and a tiny bit of 2S oil in gas. Why does it crank like 1 cylinder is low on compression?
Click to expand...
Mine does this occasionally also. It concerned me at first but not now, it always runs fine.
It's probably something in the valvetrain that briefly affects compression while sitting.
 
KnappAttack said:
Rusty valves and seats.
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That was my first thought too, but it will happen sporadically during the season also. I thought it was a hydraulic valve train(collapsed lifter)but I see a valve lash setting so I was wrong on that.
 
SPM said:
That was my first thought too, but it will happen sporadically during the season also. I thought it was a hydraulic valve train(collapsed lifter)but I see a valve lash setting so I was wrong on that.
Click to expand...
Fleecer said:
I had an RX-1 do that years ago. It was like the lifters discharged. The engine cranked like it had no compression. Once started it was normal thereafter.
Click to expand...

There's no lifters in these motors. They are a shim under bucket design, meaning that the camshaft is always riding on the bucket and in direct contact with the valve, no way for anything to collapse.

You likely have a corroded valve, run it through several heat cycles and see if it gets any better.
 
Some areas here in the UP have over a foot of snow on the ground. Put it a national forest rd after dark and run it. (Can't ride during hunting season back after dark its on).
 
stgdz said:
stop guys you are going to make Tflash tear it all the way down again.
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Customer sled. Putting fiber optic camera into it this weekend. Engine is practically brand new (maybe 1500 miles?)- was completely rebuilt last year due to previous deto (block was stripped, machined, diamond honed; new Corrillo pistons, Carrillo rods; valves lapped and shimming set, new valve seals, all new engine seals, gaskets). Ran flawless last season on Stage 3R 300HP. Stored in heated/AC storage area. Went to start this week and cranked funny. Started but ran erratic for a bit, then sounded normal. Subsequent starts, engine still has a "hitch" while cranking.
 
Valve shim out of place at end of yr last season ?
 
Turboflash said:
Just wondering if anyone has experienced a situation where a 998 has been sitting in storage all summer (since April) and when you go to crank it now (Nov) there seems to be no compression, ie motor "skips" when cranked, like 1 or more cylinders has no compression? Once started, motor seems to run normally. Sled has about 3500 miles on it. Sled was stored with ethanol-free gas with prescribed amount of Seafoam and a tiny bit of 2S oil in gas. Why does it crank like 1 cylinder is low on compression?
Click to expand...
I would say it's fuel related, once seafoam and old gas are gone it will be good.
 
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