[M.D. Holloway]

Aurel,
First off, marine engine oils are very different than automotive engine oils.

As far as marine engines are concerned, the specifications for marine applications are pretty strict. Bombardier, Mercury, Yamaha, Tohatsu, Nissan, and Suzuki engines all have their specific testing criteria to meet. In order to make a certain amount of sense of all this, in 1992 the National Marine Manufacturers’ Association or NMMA developed a specification that engine oils have to meet in order for approval to be used in marine applications. The most recent performance standard, NMMA TC-W3, is a bunch of tests for oil detergency, lubricity, pre-ignition, and emissions. The tests are actually run on various marine hp engines from a few different manufacturers like Mercury, Honda, ect…

The engine you have is essentially an automaotive engine no? If so, Gunk valvemedic treatment is really designed for automotive applications but may not be the best thing to use. It is most likely just Xylene with a little detergent. Will it remove the deposits but it may cause other problems as well. First off, the solvent may remove the varnish which is essentially oxidized oil. This is found on main bearings and other lubricated parts but rings may have a laquer on them. That is typically formed from varnish that has been introduced to very high temperatures and pressures. Laquers are really hard if not impossable to remove by chemical means. Even hitting them with aggresive solvents, acids or caustices sometimes will not remove them. Lets hope that is not the case.

But lets say you use the GUNK in your crankcase. The solvent mixes with the oil and proceeds to do it's majic. You drian the oil and add new. Do you think you got all the old oil with the GUNK in it out? Nope. You may have left up to 5% still in the crankcase. Now you add new oil and you have just contributed to the quicker demise of the new oil and maybe even contributed to the formation of more varnish that would lead to laquer because it has just mixed with the solvent and old oil. Not good. In the outside chance the GUNK is not solvent based, then they employ the use of an acid, most like crysilic acid (sp). This is effective at removing deposits but will also help mess things up if you do not get out all of the old oil.

So what to do? Well dude, your *******.











No your not, I'm just messing with you. But it sounds like you may need to do a ring job. Are you burning oil? what color is the exhaust on start-up? Any chance you can take an IR Temp gun and find out what the temps of each cylinder is? When doing so, note the position of the cylinders in relation to the exhaust manifold. This makes a big difference. Many times the pistons on the far edge may run different than the ones closer or in the middle. This is natural. Also, what engine oil and weight are you using and what is reccomended by the OEM?

Lastly, it may also be fuel related. Fuel quality has taken a beating and there are no real regs in place to keep it up to standards (save octane regs).

Get back to me with some answears to the questions. I think I may have a few low cost suggestions that may help you but it would be pre-mature to say anything yet.