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Run engine dry before layup?
|Author||Topic: Run engine dry before layup?|
posted 03-24-2002 09:54 AM ET (US)
I recently acquired a 70 hp Johnson 1993 with a remote oil tank. I have always been carefull to run previous owned outboards with mixed gas/fuel dry when through using, even if they were only laid up a few days. The manual for the Johnson says to 'not run the carbs dry to avoid hard starting'. What is best? I would think an engine laid up for a few weeks or more should be run dry? The engine runs sweet now.
posted 03-24-2002 10:27 AM ET (US)
When I picked up my new Merc 90 last week, I commented to the mechanic on the fact that there was no longer a quick disconnect on the motor end of the fuel line. He said that Merc had discontinued that to discourage folks from running the motor dry. Apparently the problem was that sometimes one cylinder runs out of mix before the other(s). Engine keeps running while 1-cyl is dry.
The manual only mentions running it dry when you are puttin in the carb spray for winter storage.
posted 03-24-2002 11:51 AM ET (US)
No do not run the carb dry on an engine that has VRO. You will fill the carb float bowls full of oil and make restaring nearly impossible. This is because the fuel & oil are mixed in a crank case powered pump (looks sort of like a Jarvic-7 hart)mounted just upstream of the carbs. If you cut off the gas all it pumps is oil.
posted 03-24-2002 04:48 PM ET (US)
Not running dry makes complete sense when explained, and I will follow my manual. However, suppose the engine will be laid up for many months? I would think the oil/gas mixture in the float bowls would get gummy?
posted 03-24-2002 11:41 PM ET (US)
Each time you buy fuel, put the proper amount of Sta-Bil in the tank. This will keep the gas good for up to 2 years. Sta-bil keeps the "lights" from evaporating out of the gas, it stops the gas from "gumming", prevents the gas from attacking rubber parts and it also works to some degree like dry gas. If you run Sta-bil all the time, it will never matter when the next time is that you use the boat.
posted 03-25-2002 02:13 PM ET (US)
I just read another reason why you shouldn't run an engine dry. Even though the engine does die, there is still some fuel left in the hoses, bowls and ports of the fuel system. This fuel, if not stabilized will form deposits as it ages and eventually this has the potential to gum up your carbs.
posted 03-25-2002 05:52 PM ET (US)
Biggest reason not to run carbs dry is still the VRO. Air mixed with either the oil or the gas in the VRO pumps was the main contributor to the demise of many a VRO equipped OMC engine. Air in the pump screws up the oil mixture, tending to make it toward the lean side of oiling, and burning up the powerhead.
Ron, I've let my 70 OMC sit for 5 months w/o running her dry. I've rebuilt the carbs once while I've owned it (6 years). If you're worried about the gas in the carbs turning sour, what about that gas in the tank?
Best thing about running the older engines dry was not having fuel leak out the front of the carb when tipped up.
posted 03-25-2002 09:23 PM ET (US)
We have a 1988 Evinrude 70 VRO on our boat. It has never been run dry nor had a carb rebuild in its 14 years. We may have just been lucky but it has worked for us.
posted 03-25-2002 11:48 PM ET (US)
I have had the carbs on my 70 gum up twice even though I always ran the engine dry. I suspect that it has alot to do with Maryland using oxygenated gas and GA and FLA not using that crap.
posted 03-26-2002 02:36 PM ET (US)
I only had 2 carbs gum up on me that were not gummed when I purchased. ! was a 1984 60hp Johnson that a carb float stuck after winter storage, no biggie. 2nd was my Yamaha after sitting 3 weeks it stuck the needle and seat which was a major pain to rip down. It happened twice. most that I talk to have this problem with Yamahas and their needle and seats if used frequently. If sitting over the winter, anything can happen on any engine brand.
posted 03-26-2002 10:51 PM ET (US)
I agree w/stabil if you do not run you motor that often..
Paul Harvey endorses it also..
I also hear about issues when vro's run dry.
Bottom line is, run your motor!
posted 03-27-2002 12:09 PM ET (US)
OMC used to have a product called 2+4 fuel treatment. It performed the same function as Sta-bil and also an anti-carbon and dry gas function. I don't know if it is available under the new owners. However I have used it in the past and it worked very well.
posted 03-29-2002 11:40 PM ET (US)
Just started the Rage after winter lay up with the first turn of the key like ussual and I put sta-bile in the fuel the last two fill ups of the season. Worked great again would not do it any other way.
Lake Breeze Rage
posted 03-30-2002 08:51 AM ET (US)
Wow I think I got a real education in the proper handling of an oil injected engine, and I needed it. I got away from larger outboards in the past [many] years and my thinking was driven by the old oil/fuel mix engines. I am quite happy to not have to drain the engine, and since my grandsons will be using the rig a lot, it will not create a problem there.
Thanks for all the help and advise. This forum has been a winner for me getting going again with a 15 Whaler. The 85 hull has come back to like new shape with a lot of compounding and waxing. Stripping the wood and revarnishing has that like new, and the 93 70 Johnson responded to a light tuneup and sings. What a great rig.
Go boating today, I am. Regards Ron B
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