Pearson Boats - Common Systems > Engine and Drive Train

Atomic 4 compression test results

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Dolce_Vita:
Another possibility for low compression is sticky valves.  The A4 is prone to sticking valves, especially if it has been allowed to sit unused for extended periods, or has gotten water in the cyls.

One way to combat this is to include some Marvel Mystery Oil in the crankcase oil.  This will help lubricate the lower part of the valve stems over time.  I generally include about 8 oz every time I change the oil.

For more severe cases, you can also include a little MMO in the gas, which will help lubricate the top ends of the valve stems.  It does produce a little smoke, and causes some additional fouling of the plugs, so I wouldn't do this as a long-term fix. 

If you do try the MMO, recheck the compression at the following oil change.

T_schlueter:
I keep MMO on hand but tend to forget about it. This compression issue will help me to use it.

Alma:
Raw water cooled is safe in the Lakes. Only advantage there to closed system is ability to run higher temp and prevent sticky valves and get very slight increase in efficiency. MMO is your best friend. Use it in gasoline only. Change the oil every 30 hours or when you run through a 30 gallon tank of gas.

https://www.instagram.com/p/B-ndThJl4yX/

T_schlueter:
Looks and sounds great!

Alma:
Thanks. We'll see Saturday when we put it back in.

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