Run carby dry between trips?

[Dezzer]

20 hp Yamaha 2 stroke.

Should it be run dry between trips (up to a month at times) or leave fuel in it.

Regards

[Scott nthQld]

i'd run it dry after every use, since your engine is not DI you can run into a alot of problems when the oil/fuel mix in the carby splits and will leave a gummy residue that will cause flow problems.

I have a 4st, and I still run it dry after every use, even though trips are usually within a week of each other.

[blaze]

why would you want to run a lean fuel/air ratio in your motor, doing this for even short periods can burn the top off your piston from heat. If you feel you must drain your fuel use the drain screws on the float chambers. Been boating for over 30 years and never drained a carbie in my life, dont have fuel problems either. Had motors sitting around for 18 months and all it takes is to pump a bit more fuel through them. A carbie dosnt hold that much fuel and a couplke of pulls and a reprime will see fresh fuel in there. This is only my opinion and others will disagree
cheers
blaze

[Noelm]

this pops up from time to time, to run your motor dry DOES open it up to a lean burn and could cause damage, but with mine, I still run it dry if I am going to (say) transport it not on the Boat (laying down) or if I know I am not going to use it for a long time , like during Winter, I do not use the Tinny much, so I run it dry before "storage" but it can cause damage for sure!

[FNQCairns]

My take on this is it's no problem, the engine is at idle with no spark advance there is not the physical ability for it to burn a hole or for it to do any damage what so ever.
Even at the point where the storkiometric (sp)ratio is that air rich the engine cannot fire there is still bulk oil in that lean fuel mixture to lubricate at those rpms.

I agree with above about the need not to do it, at least I did, now with ethanol creeping in even as an unknown additive the idea now has merit IMO, I didn't drain my carbs from 6 weeks ago and I still feel guilty about it, will probably flush them with new before I run it.

cheers fnq

[Spaniard_King]

My Take on this is if you run it dry you are removing lubrication and more importantly anti corrosion properties from the engine by running it dry. If left for some period in the wrong conditions you could have rust forming on the crank/ bearings etc. Then next time you use it it will take a period of time to acheive the lubrication level required for the engine longevity.

If you worried about stale fuel learn how to drain the carbies.

[Mr__Bean]

On my last boat I had a 200HP Black Max Mercury. Not long after I got it the oil injection alarm started to go off intermittently and for piece of mind I had the oil injection system disabled and I went back to pre-mix 2 stroke.

All good at higher revs or when under a bit of load but at idle it did seem a bit rich on oil when running it at 50-1.

When I would start it after sitting around for a bit it would certainly plume with smoke and whilst I never had trouble starting it the plume did give me the pip.

So I started to run it dry of fuel when running it on the muffs at home after each trip out, but I never run it completely dry.

Any 2 stroke will start to increase its RPM just before it runs dry. I used to run it on the muffs for a while and then when happy it had been thoroughly flushed I would remove the fuel hose. I then hop straight into the boat and waited with my hand on the switch and waited for the rpm to start to pick up a bit, then shut it straight off.

My point being, to run the fuel down in the bowl you don't have to run it completely dry, the engine will tell you when the bowls are nearly empty, and shut it off there and then before running it short on lube.

Sure, maybe not for everyone, but it reduced that big plume of smoke for me on first start up.

- Darren

[Dirtysanchez]

This is interesting, I had heaps of trouble with a whipper snipper, the fuel lines kept perishing and the bloke told me to run it dry each time because particularly with simpler 2 stroke engines, the fuel and oil separate and often the oil will move back down the line due to gravity, leaving neat fuel in the line, causing it to perish.
At the time I had a Merc (Tohatsu) 30 and I asked if it would be beneficial to run it dry between uses and he said yeah, same principle.
I've sold my share in it now, but still know the guy who has the boat, he doesn't bother and 18 months later he hasn't had an ounce of trouble, so it beats the fuggouddame ;)

[gone_fishing]

you should empty the carbies by draining or run them dry in any two stroke premix as the fuel evaporates leaving the oil residue causing no end to blockages
just let the motor idle after flushing disconnect fuel if your not putting it under load you wont cause any damage

[Tailortaker]

This is a really interesting thread because I have been letting my 2 stroke run dry when flushing THINKING that I'm doing the right thing. I have noticed that since doing it the motor is'nt smokey upon starting, I never have had problems starting my motor when cold ( '00 johnson 25hp) as it only takes one pull but just noticed the smoke difference. I probably don't need to worry about running it dry as it usually gets used once a week or two at the most so stale fuel is not an issue.
________
Mercedes-benz t80 (http://www.mercedes-wiki.com/wiki/Mercedes-Benz_T80)

[Simmo2]

I was told that 2 stroke fuel, using 'normal' petrol takes about 4 weeks to 'go orf', whereas 'premium' petrol takes 6-8 weeks???
I have always used premium in any 2-stroke I own, and had faults and problems too... am I reducing those fuel problems by using 'premium'?
My motor is used at least weekly. I havent run it dry.

[artesian]

some ppl reckon it is better to choke the motor and let it stop full of oil and fuel,

Using it more often is probably the best answer. I think I'll try it myself. Have to take the boat out dear, the fuel mix is in danger of gumming the induction system - see ya :-)

The consensus seems to be that modern unleaded doesn't stay fresh for a month or more

[Bin455]

Mate, when i picked up my boat (with a 50hp Honda) the dealer said because im in the tropics (darwin) that i should run it dry after each use due to the hot weather up here ruining the fuel a lot quicker. He also said that the #1 reason outboards come in for repairs is from the carbys gumming up and that it can only be fixed by pulling them apart.
Having said that i normaly use my boat at least once a week but when i know i will be using it within a week again i dont drain it. If im leaving it sit longer i will drain it and then run the motor once a week with the muffs.

Bin455