Engine start difficulty - Page 2

Poly · 07 September 2009, 13:12

Quote:

Originally Posted by 9D280

Personally I'd take that with a pinch of salt - otherwise diesels wouldn't last 10 minutes - they are fundamentally lean burn engines!

i've treated it with some suspicion - as I know an engine which was treated this way twice a week every week for 4 or 5 years and had no obvious problems. Given that most people probably wouldn't bother "emptying carbs" if they used it that frequently - then someone doing it say once a month seemed unlikely to cause notable damage.

Quote:

As for fuel going off in 2 weeks I can taste salt again - how man businessmen would be stuffed when they got back to their car that had just sat for 2 weeks in the airport long stay?

I am completely in agreement with you on that - I frequently use fuel that has been sitting for several months and it still seems to burn OK. Is it harder to start or give slightly poorer performance? I'm not sure if you know its old - you can convince yourself it makes a difference - but I haven't done a proper blind trial.

CJS · 07 September 2009, 13:31

Actually MikeP that is a damned good question - does anyone know the best solution/ truth to a flooded engine?

I have heard conflicting info on this one, some say to leave the engine alone for a few minutes to clear (not exactly sure how the fuel drains away but anyway.) perhaps the excess fuel in the carbs drains away of its own accord?

Someone else said the complete opposite - turn off the choke and keep pulling until the carbs clear. Which one is actually correct?

Apart from visibly seeing fuel in the water how does one actually determine if its flooded or not?

Nos4r2 · 07 September 2009, 14:21

Quote:

Originally Posted by CJS

Actually MikeP that is a damned good question - does anyone know the best solution/ truth to a flooded engine?

I have heard conflicting info on this one, some say to leave the engine alone for a few minutes to clear (not exactly sure how the fuel drains away but anyway.) perhaps the excess fuel in the carbs drains away of its own accord?

Someone else said the complete opposite - turn off the choke and keep pulling until the carbs clear. Which one is actually correct?

Apart from visibly seeing fuel in the water how does one actually determine if its flooded or not?

Either method works. Fuel evaporates if left alone-but the best way to clear a flooded engine is to turn the fuel off, open the throttle fully and with the ignition off turn the engine over for a few seconds. Try and restart it after you turn the fuel back on without using the choke.

jyasaki · 07 September 2009, 17:06

I've never really had a problem with flooded motors, but always heard that no choke and wide open throttle is best to clear the excess fuel. Turning the fuel off is probably going to end up being a feel-good thing, as it would still have to empty the float bowls before it made a difference (which, if a pull-start, is going to give you some serious exercise.) That's a guess, though.

jky

9D280 · 08 September 2009, 11:45

Yep the oil slick behind you is the obvious givaway.

Certainly the quickest waty to clear it is put the choke in (as in no choke - "closed choke" to my twisted engineering mind is that you have closed the valve and are therefore choking it ..... but I digress). Open the throttle, and pull / crank for a bit. eventually you'll pump enough of the extra fuel out thru the exhaust, and the remainder will be a suitable mix to go bang & start the engine.

Suffice to say keep your hand on the thriottle, coz when it starts you're wiiiiiide open abnd will annoy all the yotties with that awful unecessary loud noise!!

jyasaki · 08 September 2009, 15:58

Quote:

Originally Posted by 9D280

Certainly the quickest waty to clear it is put the choke in (as in no choke - "closed choke" to my twisted engineering mind is that you have closed the valve and are therefore choking it ..... but I digress).

To clarify: A choke works, when activated, by closing off the carb, restricting fresh air flow, and thus richening the mixture for cold starting.

Therefore, a closed choke is one set for the cold start configuration (choked engine, choke on, closed choke.)

To clear a flooded engine, you want little fuel and a lot of fresh air; hence turn choke off (i.e. open choke; normal running setting, unchoked) so you get max airflow, and open the throttle all the way (butterfly valves open, but little air flow for the venturi to suck fuel into the mixture.)

Sound about right?

jky

MikeP · 08 September 2009, 20:27

Jky,

You've got the better of me with that explanation, I tell you, but I think it is mostly to do with terminology and relating it to the physical little handle we've got attached to our outboard.

Let me try and get it straight in my head - and out in the forum for future searchers....

- pulling out the choke handle/lever restricts fresh airflow and hence 'richens' the mixture - more petrol, less air.

- normal engine running position is with the choke handle IN - ie, no restriction to airflow, engine running lean

- cold start needs a rich mixture of air and fuel, so you pull the choke lever OUT to restrict the airflow

- dealing with a flooded engine you want more air in there, so you push the choke handle IN so that there is no restriction to airflow.

Sound consistent with what you said ?

jyasaki · 09 September 2009, 00:27

Sounds right, Mike.

jky

9D280 · 09 September 2009, 08:38

Mike,

Spot on.

Don't you love the English language........?

jyasaki · 09 September 2009, 15:34

Quote:

Originally Posted by 9D280

Don't you love the English language........?

In this case, it's not so much language, as it is the perspective you look at the operation from.

"Choke in" can refer to the control knob position, a control lever position, or the (rather tenuous) description of what the butterfly is doing.

Given that "in", as far as controls go, may do different things on different engines, well, yeah: it's going to get confusing. Which is why I threw in the "normal operation" vs "cold start" conditions, just so we all were looking at the same thing.

I suppose we could all revert to Garf-speak, which would certainly make things clearer. Then again, maybe not...

jky

Wavesurfer · 09 September 2009, 21:38

Quote:

Originally Posted by CJS

I purchased my Honda 20 HP brand new - just coming up for first service at the end of this month.

The first few times it started practically on first or second pull from cold. The last couple of times it seems to have become more stubborn - from cold - and the last time I spent at least 10 or 15 minutes trying to get it started...

I was wondering that once everything is coupled and I have pumped the fuel through the line to engine that maybe I should - without the choke engaged pull through a couple of times first?

Any thoughts?

I have a Honda 20hp. If it has not started with the choke on/out (or partly out) it may be flooded, I have pushed the choke in and as per the manual "open the throttle grip 1/8 - 1/4 turns and start". This has worked for me so far.

m chappelow · 11 September 2009, 09:56

as a matter of intrest i decided as its a fine day to give my 4 stroke a run in the tank in the garden using some petrol which i bought about 6 weeks ago ,kept in a can in the back of my car as the car fuel gauge was not working and i wanted it there so i wouldent get stranded ,anyhow got the car fixed and thought about seeing how the outboard would start on 6 weeks old fuel ,,,engine hasent be run for 3 or 4 weeks ,, and it started and ran on the second pull ,

oujakov · 11 September 2009, 12:45

Term of "old fuel" is only relevant to fuels that are very old, like few years, or old leaded fuel from the era of carburated cars in the 70's. Other than that, in general, modern fuel will not "go bad" after only few months.

And as it has been said before, it is a great idea of emting carb from fuel before packing engine for transportation/storage.