How long on muffs

[Dave Abrahamson]

How long do you guys usually run your motor on the muffs upon returning from a saltwater day?<br />I run mine,('83 J90),about 5 minutes. Is that sufficient? I also keep it at idle while flushing and then pull the fuel line until it starts to sputter/rise in rpm's, kill it via the key....this it what the guy I got it from did every time he ran the boat and it has never given either of us a problem. Am I hurting anything by following this procedure or....?<br />I would hate to damage anything by letting it run out lean, it's such a good running motor.<br /><br />Thx all<br /><br />Dave

 

[Forktail]

Re: How long on muffs

That sounds about right. On some outboards I feel the water coming out of the pisser to make sure the thermostat opens (if it has one). This ensures that any saltwater in the block is flushed. Sometimes I even give it a taste. Warm and no salt taste, then she's good to go.<br /><br />You probably don't need to pull the fuel line. That's something done more for longer storage.

 

[Paul Moir]

Re: How long on muffs

Your top carburator will run out of fuel, but your bottom carb will keep the engine running for a while. During that time, your top cylinders are getting no lubrication.<br /><br />Pulling the fuel line on a single carbed engine might not be a good idea. It's a very bad idea on a multiple carbed engine.

 

[waterinthefuel]

Re: How long on muffs

Paul, where exactly did you hear that? The engine is running a little lean for such a short period of time that it won't hurt a thing. It's alot worse to kill it in advance and have the thing gum up over time.<br /><br />The cylinders in an outboard are so full of oil that a second or two at idle will not hurt a thing. I've done it for years, I know people that have done it for decades, with no problems whatsoever. My engines run like clocks and start right away, every time. Pulling the fuel line off is universally accepted as the ideal way to run it out of fuel.

 

[Paul Moir]

Re: How long on muffs

Actually, I heard it here. From JB I think. It's not the running lean that's the problem, it's the lack of lubrication. How long do you think it is safe to run an engine without oil?<br /><br />Personally, I dump the fuel from the carb bowl's drain (if it has one).<br /> Reference (I wouldn't want to take JB's name in vain )

 

[Franki]

Re: How long on muffs

Well, how about a middle ground..<br /><br />next time your at it.. disconnect your fuel line at idle and time now long it takes till you hear the rise in RPM..<br /><br />take 15-20 seconds off that time, and from then on only let it run for that long before killing it...<br /><br />evaporation will take care of the little bit left if your in a hot climate like we have here.<br />evapotation would leave a tiny bit of oil behind, but when you think about it, a 50th of the tiny bit of fuel left is a pretty inconsequential amount of oil.<br /><br />Of course opening the drains on the bowls is even better, but not always easy or even possible.<br /><br />I tend to have long periods of time between outtings, which is why I always do it, but if your just putting it away till the next trip out in a week or whatever, its not worth the effort. do it at the end of your season.<br /><br />rgds<br /><br />Franki

 

[Forktail]

Re: How long on muffs

There's no reason to disconnect the fuel line when flushing. That would be something that might be done for long term storage.

 

[waterinthefuel]

Re: How long on muffs

Paul, you aren't running the engine without oil. I know my little engine smokes until it dies. It's not hurting a thing.<br /><br />Frankie, it only takes an inconsequential amount of oil to clog a carb port a few thousanths' of an inch in diameter.

 

[mattttt25]

Re: How long on muffs

i would hope an engine these days could be turned off with the key and not cause a problem. just my dumb thought. i've heard of pulling the fuel line when winterizing, but it makes sense to me to keep stabilized fuel in the system and killing the engine while fogging.<br /><br />as for flushing, i run it approx 5-10 minutes. when the water spray is luke warm, i figure i'm done.

 

[Dave Abrahamson]

Re: How long on muffs

Thanks for all the replies.<br />It's interesting to see the differences in opinion on the fuel line question.<br />The pros and cons all make sense.<br /><br />Dave

 

[Walt T]

Re: How long on muffs

It should be noted that 50:1 mix is 50:1 no matter what. Leaning the mixture does not affect the oil distribution in the fuel. It affects the air/fuel ratio. Running it lean lowers the total amount of oil in the cylinder and will cause a problem if run like that for a period of time. Idling it out of fuel is generally accepted as an acceptable way to get the gasoline out of the system. Draining carburetors is acceptable also but leaves fuel in the tiny passageways that can cause problems come spring.<br />Running Stabil or fogging oil through the fuel system is also a good idea. Idling on the muffs without letting the engine overheat is fine. Do NOT rev any outboard on the muffs.

 

[UpstNYer]

Re: How long on muffs

Three 9.8HP Mercs in the family....all 20 years old or older and bought new. Only time any of them have had trouble is when someone forgets to run the motor out of fuel at idle at the end of an outing. Other than that, they've been utterly reliable. How bad can this practice be?<br /><br />If it's dumb, but it works, then it isn't dumb.<br />Bob

 

[andrewkafp]

Re: How long on muffs

Dave<br />I've asked this question on here too.. and I like 12footer's answer.. He's been around for a long time... and I have confidence in his judgement.<br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=29;t=001455 <br /><br />As well as this, I run my motor regularly on muffs in the non boating season and keep it full of fresh fuel and stabiliser.<br />Having said that.. My 81 Merc has been "Run dry" for 20 years before I owned it by the prev owner and it's still running well with equal compression (about 125) in all 4.