hybrid

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Grumpy
Posts: 227
Joined: Mon Dec 05, 2011 5:22 am
Location: Auckland

hybrid

Post by Grumpy » Sat Jul 27, 2019 2:29 am

A few months back I bought 2 gulls to ensure I got the EPC with clutch that I wanted. 2nd clutched forty plus I have and they are a really nice. Can't beat them esp with the clutch.
Anyway they were both in distessed condition but after a lot of work , head cleaning , replacement brass tank, gearbox cleaned out etc etc I got the EPC going only to find it was not passing water.
Stripping down the bottom end I found . and its the first time I have found such a mess, the entire bottom waterway system was chokka with sand clay and junk. The vertical brass tube full From just inside the water intake to around the impellor.also chokka. A solid mess. Be interesting to know where it had been used. I recall reading on line how seagulls used around Poole get serious blockages.
There are multiple mud banks around Auckland which could be the cause.

Cleaned it all up, reset points and its going champion and unlike unclutched forties it passes water in a tank faster than the Colorado dam even at slow revs and the prop on just like my other clutched forty plus.Strange.
Then I set to trying to get the second of the gulls I had bought, an lls with shiney tube and some good looking bits but lots of abuse also.
Can[t afford an electric car but I want to be modern and have a hybrid so I decided to mix together the better bits from this lls , some good bits from a silver century and bits here and there.
LLS bits, tank bracket , carb lever, bottom end which looks good and the rear gearbox face looks mint instead of usually looking rather battered.
SIver cent bits, power head, etc.
Best of all I am using a villiers carb, cleaned up .
Had to creae a new longer length acc cable and a longer fuel line to accomodate this .
Had a home made adaptor to allow fitting this villers carb where normally a larger mouthed amal carb goes.
Anyway she goes and in tank it sounds magnificent.
I believe centuries reach up to 3800 rpm and silvers up to 4200. This beast is probabley reaching 6000rpm although there is a faint doubt about that Very faint.Anyway going to try out my rev counter as Nudge showed me years ago and it will be interesting to see the results.
Believe I have taken up enough space .

Journeyman
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Location: Pembrokeshire

Re: hybrid

Post by Journeyman » Sun Jul 28, 2019 9:57 am

Hybrid, ha for a moment there I thought you might be going to convert it to potato power, some sort of gear box with a crank on the end of it! It’s finding a nut to go on the end of the crank that’s the difficult part :roll: .

Dave.

Grumpy
Posts: 227
Joined: Mon Dec 05, 2011 5:22 am
Location: Auckland

Re: hybrid

Post by Grumpy » Sun Jul 28, 2019 10:56 pm

Definitely not anything to do with spuds.
Other than frozen supermarket chips no spuds cross my door now, not prepared to risk 70 plus years of developing the body I possess.
Mind you I recently purchased a bag of frozen chips , on special, to find out they were made in the Netherlands. Why we need to import spuds way down here from there is crazy.
And they were shocking .Obviously the wrong variety perhaps better for daffodil cultivation.
I have some early rellies from Donegal and Tyrone so my tastebuds are top notch .
Perhaps a good reason I have no need to seek out any nuts.
After more trials on my hybrid I have found that , perhaps due to the longer fuel pipe, I nned to use the carburetor primer more and once started to keep the choke on for at least 30 or so seconds until it settles down.
Perhaps due to the longer distance for fuel to penetrate the block.
All highly subjective details which utterly confuse me.The lengthened fuel pipe is constructed using the remains of 2 old ones and joining with an alluminuom pipe 25 to 30mm in the middle 30mm each way, clamped and not a spec of fuel to polute my immaculate back yard.
Once going she does perform well although only a thorough thrashing would prove its worthiness.

Chris B
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Joined: Tue Jan 29, 2019 2:37 pm
Location: England

Re: hybrid

Post by Chris B » Sun Jul 28, 2019 11:20 pm

Re: "After more trials on my hybrid I have found that , perhaps due to the longer fuel pipe, I nned to use the carburetor primer more and once started to keep the choke on for at least 30 or so seconds until it settles down."

You say that you've joined the fuel pipe with a piece of aluminium tube. Presumably you slid the ends of the fuel hose over the ally tube and brought the ends of the hose together so that your tube is hidden inside. If that is so, then perhaps the inside diameter of your connector tube is restricting the fuel delivery rate to the float chamber a little more than the engine likes. This might account for the symptoms you describe: the extended tickling time and a bit slow to come off the choke.

As it's slow to come off the choke, I wonder if a flow restriction caused by the inserted piece of tube might be causing the engine to run a little bit lean. If that's the case then it'll probably become more noticeable when you run the engine under load with more throttle.

Just a thought. But it might lead to a more useful suggestion from elsewhere!

Chris

Grumpy
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Joined: Mon Dec 05, 2011 5:22 am
Location: Auckland

Re: hybrid

Post by Grumpy » Sun Jul 28, 2019 11:42 pm

Perfect.
Yes the 7mm aluminium tube is fully inside the rubber tubing .
The internal diameter is less of course but considering its a seagull the amount of fuel being delivered is surely way more than needed.
There is no known impediment or blockages to the fuel line and I was careful not to overdo the clamping where the join was.
I ran it on 10-1 with the carb screw dead level with the piston. It smoked but to my untrained eye seemed aok.
Cheers.

Grumpy
Posts: 227
Joined: Mon Dec 05, 2011 5:22 am
Location: Auckland

Re: hybrid

Post by Grumpy » Sun Jul 28, 2019 11:46 pm

Have taken aboard that I will need to understand and correct this lean/ rich running under pressure.
Perhaps also change my fuel ratio.
cheers

Chris B
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Location: England

Re: hybrid

Post by Chris B » Mon Jul 29, 2019 12:15 am

A snag with fluid flow systems - in this case your Seagull's fuel delivery line - is that the effect of internal restrictions and friction on the delivery rate is cumulative.

This means that the gauze fuel filter in your tank + the restriction caused by reduced x-section of your aluminium coupler + restriction caused by secondary fuel filter (if any) + frictional drag caused by the internal surfaces and irregularities in the entire delivery system, can all add up to produce a seriously limited fuel delivery rate. On top of all that, the carburettor designer then puts the brakes on even harder, by deliberately shoving a needle valve right in the way of what's left of the fuel flow!

The effect of all the foregoing obstructions is usually not so critical if the fuel flow is driven by a pump, but in a gravity fed system that relies on a very small pressure head - which is what you have in a Seagull - the cumulative effect of all those restrictions can have quite serious consequences for fuel flow - and consequently engine performance.

Another thing to be aware of is that you don't need to reduce the effective internal diameter of a pipe very much in order to halve its cross-sectional area. For this reason, a surprisingly small reduction in pipe diameter (even if the reduction is only a short length of tube in a very long pipe!) can have a big impact on the fuel delivery rate.

Cheers,

Chris

Grumpy
Posts: 227
Joined: Mon Dec 05, 2011 5:22 am
Location: Auckland

Re: hybrid

Post by Grumpy » Mon Jul 29, 2019 12:45 am

Truly a wealth of info, unbeatable .
Will go ahead with all your advice determined to keep this Villiers onboard.
Am already contemplating a better fuel line for starters.
Thanks.

Chris B
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Joined: Tue Jan 29, 2019 2:37 pm
Location: England

Re: hybrid

Post by Chris B » Mon Jul 29, 2019 1:06 am

Now we're on the subject I've remembered a real-life example that demonstrates exactly what I've been explaining.

Some time ago I read an account written by a Seagull owner who had installed an extra in-line filter in his Seagull's fuel hose. It was one of those fancy glass jobs that lets you see what's going on inside and it seemed like a good idea.

Having carried out the modification, he was subsequently a bit bemused to discover that the engine wouldn't run properly. It eventually occurred to him that the two filters (the original plus his new addition) might collectively be producing too much restriction in the fuel flow, so he removed the original gauze filter from the Ewarts fuel tap, leaving just his new in-line filter in-situ.

And as if by magic, the engine ran perfectly again.

Chris.

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Charles uk
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Location: Maidenhead Berks UK

Re: hybrid

Post by Charles uk » Mon Jul 29, 2019 1:14 am

Good suggestion Chris!

As a matter of interest Grumpy, could you measure the fuel flow?

Just turn off the fuel tap after half filling the tank & ensuring the vent is open in the fuel cap, remove the float bowl & holding a jug under the the carb, turn on the fuel tap for one minute & let us know how much fuel you collect.
Make it idiot proof and someone will make a better idiot.

Grumpy
Posts: 227
Joined: Mon Dec 05, 2011 5:22 am
Location: Auckland

Re: hybrid

Post by Grumpy » Mon Jul 29, 2019 3:20 am

Charles uk, yes I will measure the tank but will have to wait till tomorrow due to visiting duties,5 mins after I'm off this computer.
Chris, I am in the process now of re corking a fuel tap which I wiil defilter and try out asap

cheers again.

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Charles uk
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Re: hybrid

Post by Charles uk » Mon Jul 29, 2019 8:19 am

Don't damage your fuel tap before you know if it's part of the problem.
Make it idiot proof and someone will make a better idiot.

Chris B
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Location: England

Re: hybrid

Post by Chris B » Mon Jul 29, 2019 11:03 am

Grumpy: I'd suggest that a useful approach might be to first get rid of your fuel hose coupling tube and see if the extended tickling time and choke time return to normal.

You'll probably only achieve that by replacing your existing two pieces of short hose with one new piece - which in all honesty might not be a bad idea. Assuming that your ally tube coupler is only being used because you currently don't have a long enough single piece of hose available, removing the flow restriction caused by that tube might well solve your problem.

Regarding the Ewarts fuel filter, I agree with Charles. I think it would be a shame to remove the Ewarts filter just to test a theory. Instead, I'd focus on finding a way to do without the ally tube inside the fuel hose. Perhaps more importantly, if that's the only filter in the fuel line and you remove it, you'll end up with unfiltered fuel arriving at the carburettor - a situation which might ultimately add to a fuel flow problem rather than alleviate it!

So to sum up, and at the risk of being boringly repetitive, I'd get rid of the ally tube hose coupler and then test run the engine again. I think that if you do that, you'll probably find that starting & running have returned to normal. If not, then a bit of loose crud that's moved to a bad place might be the culprit, in which case you'll probably need to consider dismantling and cleaning the fuel delivery line and carburettor.

As Charles observes, it would also be interesting to know what your current fuel delivery rate looks like - although that information will probably only be of diagnostic value if you've got something to compare it with.

Cheers,

Chris

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Charles uk
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Re: hybrid

Post by Charles uk » Mon Jul 29, 2019 11:42 am

Chris if you look at the size of the needle valve fuel aperture & the fuel consumption per hour of a FPC at full chat.

So if Grumpy lets us know how much fuel will flow into the float chamber in 60 seconds with only half a tank of head, we might be able to make an informed guess about if it's the restricted fuel pipe that's the root of his problem or should he be looking elsewhere.

This doesn't require special tools all we need to know is, more or less than half a cup full per minute at his usual fuel mix.
Make it idiot proof and someone will make a better idiot.

Chris B
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Location: England

Re: hybrid

Post by Chris B » Mon Jul 29, 2019 12:04 pm

Charles: yes, I entirely agree. And the difference between success and failure may well be represented by nothing more than the difference between a slow drip and a slightly quicker one.

Grumpy: there's a small detail that I forgot to include in my previous offering....

Over the years, a very thin layer of sticky 2-stroke residue will have accumulated on the inside surface of your fuel hose.

Now, if the piece of ally tube you inserted in the fuel hose is a snug fit and has sharp-edged ends (as they will be if you cut the tube with a hacksaw and didn't dress or chamfer the ends), the insertion process will almost certainly have "shaved off" some of the gummy petroil residue from inside the hose.

Depending on where it's ended up, that displaced gum could contribute to an already reduced fuel flow. This might sound like an insignificant detail but when carburettors are involved, seemingly insignificant and invisible details can become major issues!

Sorry to drone on - just trying to help.

C

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