Decarbonizing 1999 Johnson 175 Carb.

[Michael Vezzosi]

110 hours on the 20MA. Any insight, suggestions, opinions, warnings? Just buy the Johnson brand can, and follow instructions? Sounds pretty straight forward. Never done it. Too late?

Burn cheap grade and premix. Last years remaining half tank has been Stabilized. Run every six weeks. Just recently learned of Quick Start. Guess I should have read the owners manual. Any other assistance before I fire her up. Thanks. Part II.

[Capt Chuck]

Vezo

First off, I have a 1999 Johnson. I use the fog every 100 hours. I burn midgrade fuel along with the OMC 2+4 fuel conditioner and Yamaha ring free every tank and burn OMC oil. I don't think it is too late to do it.

BEWARE, VERY IMPORTANT
Make sure you burn all the decarb mixture out thoroughly at idel speed before you get it on!!!! (You should not be able to smell it)

[Michael Vezzosi]

Thanks Capt. Chuck. I just had my first service with the Yamaha 60 on the Whaler. Bought the RingFree as well. Pretty pricey stuff. $1/oz. Wow. So you are running it in a two stroke, huh? Haven't bought the Johnson stuff, but I guess it is a spray that you shoot into each cylinder after the engine has been run long enough to come up to temp.? Then spray the rest of the can into the airbox while she is idling? Is this pretty close? Only other thing I've heard is massive amounts of light/white smoke is normal? Thanks again. Mike.

[Capt Chuck]

Mike

There is a valve on the port side of the motor that you screw the nozzel into. Read the can as I think you give two 20 second squirts per cylinder after warm up. You squirt until the engines dies and then wait a few hours before restart. The airbox thing is news to me. The excessive smoke is normal, as mentioned above, just make sure you get it all out at low speed. I am not the expert here as my motor mech races the Johnson and was in the initial development of the 250hp 6 cylinder with OMC. He told me to use the ring free in my 2-stroke along with the 2+4 conditioner. Knock on wood, I have not had any motor failures with my last two OMC's

I think we need a expert motor mechanic to help us on this board

[Bigshrimpin]

Capt Chuck . . . I agree . . . maybe we can all pitch in a buck or two every month and have some Tech answer our questions!!

I've done this with Powertune and the Bombardier product. There's a write up on boat setup . . . I followed the FICHT decarb instructions (which is not with me any longer).

Here's a link to the Carb Version.
http://www.boatsetup.com/Decarb_Carb.html

But for my carb motors . . . I just followed the instructions on the can of powertune.
--------------------------------------------------------
On the Blown up Merc XR2 that I got for free . . . I tore it down and you wouldn't believe the carbon build up on the piston heads that eventually caused piston #5 to bite a ring and paint some pretty aluminum streaks on the cylinder wall. The carbon buildup was really thick (Looked like someone was cooking BBQ ribs on the grill). So . . . if your motor is still running . . . it's never too late.

Remember to clean off your plugs with some left over spray or replace them after you decarb.

[Michael Vezzosi]

Big Shrimpin', great point to have spare plugs close at hand. First question, which brand name is OMC? Second, I assumed you did all of this right in the yard, on trailer. Just make sure you burn it all off, right? Or do I need a day that I can dunk and run, afterwards? Thanks. Part II.

[Bigshrimpin]

OMC's Decarb spray product I believe is called "Engine Tuner". It's been a while. I know Merc's product is called powertune and Yamaha's is Combustion Chamber Cleaner. I don't think there's too much difference b/w them.

[Michael Vezzosi]

Thanks, Bigs. Appreciate it. Does the 99 have threaded valves near each cylinder that this hose threads onto (for 20 or so seconds)? Guess I have never looked that closely. Part II.

[Capt Chuck]

Does the 99 have threaded valves near each cylinder

No, one valve for the engine. Count the squirts x number cylinders you have

[Trayder]

Vezo-

as Chuck mentioned the valve, a schreader valve ( like the valve on your car tire) is located on the lower section of the engine towards the front of the engine part of the fuel system, ussually has a red lever on it.