How to Winterize 2-Stroke Motor That Only Runs Half of Cylinders at Idle Speed?

[jaykchan]

I would like to know the proper way to winterize a 1995 Mercury 115 HP 2-stroke motor that only runs the top 2 of the 4 cylinders at idle speed. I want to remove all the gasoline from carburetors before I put the motor to storage. But the usual way of winterizing doesn't remove all the gasoline from the carburetor (run it for a while and then spray fogging oil until the motor stops). Moreover, this motor only runs the top 2 of the 4 cylinders at idle speed anyway. Therefore, the bottom 2 of the 4 cylinders are not running anyway. I am wondering how to properly winterize this motor. Should I try something like this:

1. Add stablizer in fuel (this I have been doing anyway). I don't need to pre-mix oil because the motor is oil-injected.

2. Remove the silencer from the outboard in order to reach the air intake of the carburetors.

3. Run the motor at higher speed than I normally do during winterizing to force the motor to run on all 4 cylinders. Of course I will not put the motor in gear. Let it run for 10 minutes to make sure treated fuel is inside the fuel system. How can I tell if the motor is running on all cylinders? Do I run the motor in a water tank instead of using an ear muff to properly cool the motor that is running at moderate speed?

4. Disconnect the fuel supply from the motor, and start spraying fogging oil into the air intake of each carburetor. Because the motor is 2-stroke, it needs oil to lubricate the engine. Without fuel that has been mixed with oil, the engine will not be lubricated. Therefore, I need to spray fogging oil to keep the motor lubricated. Keep spraying fogging oil until the motor runs out of fuel and stops.

5. Drain the fuel bowls. They should be empty by now (hopefully).

6. Put the silencer back to cover the air intake of the carburetors.

7. Remove the spray plugs and spray fogging oil into the holes. Cover the holes with a rag to avoid oil spill. Try starting the motor in order to ciculate the fogging oil inside each cylinder. Put the old spark plugs back.

8. Move on to the lower unit...etc.

Does this plan sound right? Is there anything that I should change?

I talked to another boat owner (who happens to be a car mechanic). He said he would not run the motor dry. He would drain the fuel bowls from his motor, and then he would use compressed air to blow all the fuel from the carburetors and the fuel lines. But he said this is tricky because someone can mistakenly blow the float out of alignment or something like that.

Please let me know what you think. Thanks.

Jay Chan

 

[79Merc80]

Re: How to Winterize 2-Stroke Motor That Only Runs Half of Cylinders at Idle Speed?

First off, there is no need to run your engine above an idle. All 4 pistons are moving. How your engine only runs on the top 2 is only the top 2 carbs have idle jets. There is just enough fuel/oil being sucked into the bottom cylinders to keep them lubed, but not enough to make any power. With that said, since you always run stabalizer in your fuel, it's not a big issue since the bottom carbs don't use much at idle. If it was my engine, I would let it idle to operating temp, fog the bottom 2 and then the top 2 till it dies. The bottom 2 shouldn't expell the fogging oil like it would if it were firing and making power normally. And besides that, you should never run an outboard in neutral at the RPM's it takes to activate the bottom 2 which is about 2200 RPM. Also, in #7 of your list, don't try to start it to circulate the iol, jsut turn the flywheel (With the battery disconnected of course) once or twice around. IF you want to drain the carb bowls, just uncrew the drain on the bowl. There really isn't a need to spray the oil into the holes. It get's it while you are choking the engine.

Hope this helps.

Craig

 

[CharlieB]

Re: How to Winterize 2-Stroke Motor That Only Runs Half of Cylinders at Idle Speed?

You r plan is pretty close to what I do, with a couple minor differences.

#3 A fast idle of 1800 to 2000 is adequate to begin pulling more fuel thru the lower carbs

#4 Remove the float bowl drain to empty each carb, it is not necessary to disconnect the fuel hose and try to 'run the carbs dry'

I like to use 2 cans of fogging oil and lighty spray two carbs at a time until I get the motor smoking like an old train, then start spraying as heavy as possible till it actually bogs and smothers the motor dead. Drain the fuel and be DONE. The cyls will have plenty of oil in them.

Skip #7, it's done already.

 

[jaykchan]

Re: How to Winterize 2-Stroke Motor That Only Runs Half of Cylinders at Idle Speed?

I am glad that I have received some helpful replies.

Based on the replies that I have got from Craig and CharlieB, I believe I don't really need to remove _all_ the fuel from the fuel system. All I need to do is to drain the fuel bowl of each carburetor, and that should be enough. Because I will not remove all the fuel from the fuel system, this means I don't really need to worry about if the bottom 2 cylinders fire up at idle speed or not. The motor will be OK as long as some fuel/oil mixture being sucked into the bottom 2 cylinders to lubricate them even at idle speed, and as long as the pistons in the bottom 2 cylinders are still going through the motion at idle speed (to distribute the fogging oil).

The reason why I was thinking of removing all the fuel from the fuel system has to do with my other outboard that also has a carburetor problem. That is a small 8hp Yamaha 4-stroke outboard. I didn't run the motor dry before putting it in storage, and its carburetor developed problem. I was told that the small Yamaha outboard has a very tiny jet that can easily clogged. With the fuel that has ethanol, I was told that the new and proper way to winterize the small Yahama outboard is to run it until it runs out of fuel. That's why I was thinking of doing the same to my larger 1995 115hp Mercury motor. But now I think of this, my old large outboard is not likely to have tiny jets in the carburetor. Its jets must be big. Therefore, it is not likely to develop the problem as easy as my small outboard. I guess I worry too much.

With the suggestions coming from forum members, I have revised my plan to be this:

1. Add stablizer in fuel (this I have been doing anyway). I don't need to pre-mix oil because the motor is oil-injected.

2. Remove the silencer from the outboard in order to reach the air intake of the carburetors.

3. Remove the propeller because we will need to put the motor in gear.

4. Run the motor in gear at idle speed with proper water cooling. Let it run for 10 minutes to make sure treated fuel is inside the fuel system, and to make the grease in the lower unit to become runny.

5. Lightly spray fogging oil into the air intake of each carburetor. When the motor is smoking "like an old train", start spraying heavily. The motor will bogs and smothers and stops.

6. While the grease in the lower unit is still runny, change the grease in the lower unit.

7. Drain the fuel bowls. There will still be some fuel left in the fuel hose. We will not do anything about this - leave good enough alone.

8. Put the silencer back to cover the air intake of the carburetors.

9. Grease the propeller shaft and put the propeller back.

10. Leave the old spark plugs in place. We will replace them when we re-commission the motor in spring.

I believe this should be good. If some steps are not right, please let me know.

Thanks.

Jay

 

[Bamaman1]

Re: How to Winterize 2-Stroke Motor That Only Runs Half of Cylinders at Idle Speed?

My first suggestion is to find a source of 100% gasoline, and use fresh fuel before fogging it.

My boat has been in a boathouse for the past 26 years, and I've never really winterized the 1985 Yamaha 115 hp 2 stroke engine. I just throw 4 new plugs in it and run the gasoline out of the engine until it shuts off. I'll come back in the Spring with full tanks of fresh fuel.

The 90/10 fuel currently in use will often separate and an acid is produced that eats anything rubber. The membrane in the fuel pumps are rubber, and must be watched closely. They're easily replaced, however. You've also go to watch the fuel filters closely when using 90/10 fuel.