Do you run your engines out?

boatster_sr4 · 31 October 2005, 18:58

Theres a discussion started on another forum about the benefits vs. problems with running your engine out of fuel at the end of the day. Some claims were that if you didn't your carbs would gum up and you'd have to clean them more often. Others claim running the engine out leans the fuel and damages the motor as well as not being good for certain motors that premix oil (2 strokes). Others mention uneven fuel in carbs at runout causes uneven firing of cylinders, "bad".

I always run my engine out of fuel at the end of the day. I never know if I'm going back out in a week or a month.

I was wondering what the fellow Ribnetters do? And whats your take on this issue?

Jizm · 31 October 2005, 19:02

It depends when I think I'm going out next, like you. If I haven't used the boat within 3-4 days, I go and start it up in the bin until it runs out of fuel. The guy who services mine told me it was better to do this. He also said it was better to run a motor than winterise it if possible to do so. Just my input!

Swifty · 31 October 2005, 19:27

I never run mine out deliberately. Just off the key after flushing out. If you run it out then wheres the lubrication coming from?
If I need to empty the carbs, then I open the drain on the float chambers and flush through any residue and crap.

Tim M · 31 October 2005, 19:38

I have an ex-RNLI engine which has a tap for draining the fuel out. Very handy

DJL · 31 October 2005, 20:03

I used to run my old Suzuki out of fuel, but these days if the engines going to be left for any period I prefer to drain the fuel from the system - that or run it occasionally.

Not to mention it takes about 35mins for my 4-stroke to burn of the fuel in its fuel system

Pete7 · 31 October 2005, 20:04

If its a 2 stoke Yam or Suz then the oil is injected into the cylinders separately from the fuel.

boatster_sr4 · 31 October 2005, 21:03

I believe my Tohatsu 50 2 stroke is the same. The oil gets injected after the carbs thus its always lubed as long as the engine is turning. I imagine the larger 4 stroke motors would be just like a car, not much worries for clogging up, just have to make sure you use it periodically or add fuel stablizer for longer storage. Oil fuel mixed motors probably could be a little more vulnerable to the whole run out lean out lack of lubrication issue I would imagine.

ADS · 31 October 2005, 21:12

I may be wrong here! But I was once told that on an auto lube/ oil injection 2 stroke outboard the oil injection only really cuts in at higher rpms. Therefore, before stopping the engine, it was good to blip the throttle as this lubricated the engine. Am I right in thinking this? Sorry to hi-jack your thread Tim!

regards

Alex

boatster_sr4 · 31 October 2005, 21:27

Quote:

Originally Posted by ADS

I may be wrong here! But I was once told that on an auto lube/ oil injection 2 stroke outboard the oil injection only really cuts in at higher rpms. Therefore, before stopping the engine, it was good to blip the throttle as this lubricated the engine. Am I right in thinking this? Sorry to hi-jack your thread Tim!

regards

Alex

Alex,

The way I understand it, oil is constantly being injected. If the motor were run at idle without oil it would certainly wear out. The oil injection pump increases oil flow as the motor is throttled up. I have bleed my oil injection pump at idle and the oil certainly flows. "Blipping" the throttle would dump more oil but you'd probably have to cut the engine out immediately after otherwise it'll just go out the exhaust.

ADS · 31 October 2005, 22:28

Quote:

Originally Posted by boatster_sr4

Alex,

The way I understand it, oil is constantly being injected. If the motor were run at idle without oil it would certainly wear out. The oil injection pump increases oil flow as the motor is throttled up. I have bleed my oil injection pump at idle and the oil certainly flows. "Blipping" the throttle would dump more oil but you'd probably have to cut the engine out immediately after otherwise it'll just go out the exhaust.

Cheers Boatster,

I don't tend to do anything really, my boat is lucky enough to be stored in nice warm garage, so the engine doesn't tend to get damp, like it would outside.
I don't usually winterise it, because the boat gets used all year round, although it is treated to a full service at the beginning of the season.

regards,

Alex

jwalker · 31 October 2005, 22:39

If a 2 stroke engine is running properly, it is not lubricated by the oil/fuel mixture, it is lubricated by the oil. The petrol content evaporates from the mixture and leaves the oil behind. Plainly, the oil in the crankcase will be thrown around in a mist and gets drawn through the motor and burned but that's just an unfortunate side effect of 2 stroke operation.