DECARBONIZING A MERC.

[Grizzly]

My 850 Merc is starting good again, thanks to your help. WE have a couple of nice days here and I am about to decarb my engine. The instructions say, after bringing up to operating temp, set motor in horizontal position and level pistons to close ports. I tilted the engine, and let the trailer jack down, but that doesn't bring the motor horizontal. Is this enough? I could take it to a hillside but it would be a chore as I have nuts bolts and tools all over the boat. How do I know if the ports are closed? I remember seeing something here about grounding the spark or bypassing the switchbox when you turn it over several times to remove the cleaner. Any thoughts? Motor is 1974 850 Thunderbolt ignition. Product is OMC engine tuner, recommended by dealer who sells both brands. Sorry about the long posts. I'm spending a lot of time at home recovering from rotator cuff surgery. The wife, bless her heart, doesn't give me a chance to talk much. Life is good! Thanks again. -G.

 

[Fouled Plug]

Re: DECARBONIZING A MERC.

Closed ports? Never have used that method. I generally use Merc's Power Tune or a can of Deep Creep for decarbing. I'm not sure if it's truly necessary to have the ports closed, but I'm sure someone else here has used OMC's stuff and will chime in. And I just fire it up after the soaking is done, and blow lots of smoke!

 

[fin addict]

Re: DECARBONIZING A MERC.

I have just decarbed my Yamaha. I used the Yamaha brand, Instruction are to run engine, spray thru the carbs and let sit for up to an hour and run for 10 min. Not a hard process. Check out the yamaha brand.

 

[petryshyn]

Re: DECARBONIZING A MERC.

Griz<br />The ports are closed when the piston is near TDC, (near the plug). It won't happen for all cylinders at one time.If you really think about it, that would be a good method. If the ports are closed, and the pistons are verticle, spraying in through the plug hole would give the best saturation throughout the ring-land and piston skirt area. Thats where the build-up is a big concern. There would also be splash back which would address the combustion chamber. There is alot of waste when spraying in carbs. This certainly would concentrate on the problem areas. I like the idea.......<br /><br />my humble opinion....

 

[alcan]

Re: DECARBONIZING A MERC.

Hi Grizzly.<br />I have used all the brands. They all work. <br />The method you discribe is for a severe problem (ie stuck rings, no compresion, cylinder won't fire). I belive there are instructions to mix with fuel for maintence.This is with the OMC product. Dosn't sound like you have a severe problem to me. Good luck have fun.

 

[Grizzly]

Re: DECARBONIZING A MERC.

Thanks for the help, all. Shematic, you were right on the mark as always, I nearly went crazy trying to level out all 4 pistons, which woudn't have closed all the ports anyway. The product seems to be a high expansion foam, which stays in the cylinders nicely. After 1hr. I let the motor down and I could not believe the sludge that ran out. Then I spun the motor to clear the cylinders, and believe me, you don't want to be behind the motor when that mess comes spraying out. Goes about 15 ft. dont do it in your shop. Owned the motor about 15 years, got 20-30 Hrs. on rebuild and the motor never sounded better. Forgot what it was supposed to sound like. I didn't know you were supposed to decarb. Read about it here. Thanks to you all and have a great day! -G. <<<<<<<<<