fuel/oil additives

[scubadog]

I have twin 200hp 1987 motors on my boat. The engines have no use over the last 4 years. I have low compression on one of the cylinders of the port engine and varied compression on the starboard. Is there any additive I can use in the fuel or oil that may help the compression?

Is there a fuel additive in general I should be running for the engins. I emptied and clean the fuel tank before fill it.

[robert graham]

If the compression is really low due to mechanical problems, then additives won't help, but if there is carbon on rings, in grooves, exhaust ports, then you could run a tank of gas with a "deposit removal" dosage of Yamaha Ringfree(2 ounces/gallon I believe),and it might free things up for you. It could be worth a try. Good Luck!

[99yam40]

Motors that have not turned over for 4 years may have rust in the cylinders and on the bearings and crank. Run it at your own risk.
I would find out what shape it is in before running it

[robert graham]

My 2nd on what 99yam40 said. If motor wasn't stored or winterized properly, then it could have corrosion on shiny internal parts. Was it stored inside where it would be dry and out of the weather/elements?

[jimclemjr]

Kano company in Nashville makes Kreen 'motor tonic' they call it, which is a carbon attacker and cuts internal crud etc. I have used successfully in autos but have not needed to try on 2 strokes. You could contact those folks who are very nice or check out their site to see if they have a recommendation. In a four cycle you run it both in crakcase and in gas, can also use in a diesel. May be worth a try based on alternatives.

[robert graham]

If your motors will start up and run, then go ahead and run the Ringfree decarb through them, hope for the best regarding any possible internal corrosion. Maybe your motors are fine, just need running, decarb. Always good to fog/winterize motors for long shut down periods. Really not much to it with a can of fogging oil. Lots cheaper than new/rebuilt powerheads! Good luck and keep us posted with what you find!

[scubadog]

The engines run and sound fine. I had 2 different mechanics go through both units. Both were impressed. I have had the boat out twice now and have no issues getting up to high rpms. Very quite. I know boat was put away professionally when it was winterized 4 years ago. I was only looking for a fuel additive that may help loosen things up and or help with new gas mixtures.

Thanks.

[robert graham]

Sounds like you're in pretty darn good shape, but it wouldn't hurt a thing to do the Ringfree decarb, especially with older motors, which could have some carbon. You can decarb with Seafoam also, but I like Ringfree. Good Luck!

[robert graham]

Also, it's a good idea to run the "carbon preventive" dosage of Ringfree and the Stabil all the time going forward. Install fuel/water separators and you should be good to go! Cost of the Ringfree and Stabil are nothing compared to motor repair or replacement! Good Luck!

[scubadog]

You run both Sta-bil and Ring Free in the tank at the same time??

[rodbolt17]

buy a can of yamaha combustion chamber cleaner,follow the instructions on the can.
retest compression.