Decarbonizing a 9.9 four-stroke?

[warhawk]

I have decarbonized my Johnson 150 two-stroke easily (because it has the screw-on attachment for the Engine Tuner can). But I am stumped as to how to proceed with decarbonizing my 2002 Johnson 9.9 four-stroke. There is no such attachment, and I don't see how to spray into the carburetors with the engine running, as I do on the 150. Any advice? Thanks.

 

[rndn]

Re: Decarbonizing a 9.9 four-stroke?

4 strokes typically do not build up carbon like 2 strokes do. When was the last time you decarbonized your car or lawn mower engine? Same engine concept.

 

[iwombat]

Re: Decarbonizing a 9.9 four-stroke?

Not a big necessity like it is in a two-stroke. However, treating it to some gas with good detergents (Chevron), or any number of gas additives for cleaning up carbs and valves (like seafoam) is a good idea periodically. It doesn't hurt to run seafoam in your oil either to clean out some sludgy passages or remove some build-up. Just follow the directions on the can for mixing in crankcase oil.

 

[ezeke]

Re: Decarbonizing a 9.9 four-stroke?

There is no reason not to do a seasonal de-carbon treatment on a four-stroke. The easiest way would still be according to Capt. Bob Dunkleberger's small tank method as described in the Engine FAQ Forum:
http://forums.iboats.com/showthread.php?t=158076

Check the BRP/Evinrude maintenance chart here http://www.evinrude.com/NR/rdonlyre...55-6BC1C69789FB/0/em_maintenance_schedule.pdf