FPL won't runwithout choke

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mrlmd
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FPL won't runwithout choke

Post by mrlmd » Sat Dec 28, 2019 8:33 pm

High guys, Marc here, from the western side of the pond, longtime Seagull owner, looking for a little helpful advice.
I have 2 Seagulls, an EFPC 2222AA0 from Jan'80 that I have owned since its' birth, and an FPL1689CC6 from March '76., both of which I have recently resurrected from the dead. Both of these were completely buried under saltwater and sand for a while from a hurricane we had here last Oct 2018, and were laying neglected under my house for over a year (my bad) 'till I decided to see if they could be restored to service. They were both filled with sand, the pistons were stuck, the ignItion coil on the EFPC rusted and corroded beyond repair.The FPC piston was also totally rusted in the cylinder and that whole thing was totally useless except as a paperweight or work of art. Both gas tanks were full of goo and crud. Even the carbs had sand in them.
The EFPC needed a new Wipac III ignition and a few other minor parts I got from John at SOS, and now starts and runs unbelievably well, as good as new. The FPC got a new cylinder block, piston, and rings, and interestingly, it's Wipac II still works well. I changed the needle to convert the carb from 10:1 to 25:1 fuel mix so I only need to have one fuel mix instead of two and John told me these motors actually like the 25:1 better.
The problem I have is that the FPL will only run on full choke, if I try and open it, even after a few min. running, it will die. It also doesn't like to idle at slow speed, only runs at 1/3- 1/2 throttle, but runs great at top speed. The other one, the EFPC, starts immediately, I can turn the choke off right away, and can tick along at a really slow idle 'till I kill it. Pumps water in a steady stream even at idle.
The FPL has a great spark, at the points and at the plug. Gaps are both 0.02". I have fresh fuel. I have thoroughly cleaned the carb in an ultrasonic cleaner multiple times using Pine Sol, vinegar, carb cleaner, and fine wires through the jet, and the air passageway at the upper end of the centerpiece and jet, accessible after removing screw "A". I have played with adjusting the needle height both up and down by turning the screw above the needle in and out. I still cannot get it to run without full choke or get it to operate at slow speeds.
The only other thing that is not perfect with the FPC is that it has a small oil leak down the driveshaft casing tube at the junction with the bottom of the crankcase. I don't think this would result in an air leak to lean out the mixture and I can live with this, but I'll probably take it apart again and seal it with some gasket compound.
So tell me what to do next and how to fix this.
Thanks.

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Nudge
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Re: FPL won't runwithout choke

Post by Nudge » Sun Dec 29, 2019 3:15 am

Hi,
First off Seagulls leak dont worry about the oil that leaks out from it.

Have you cleaned the filter inside of the fuel tank? Your problem is a fuel issue (not getting enough fuel) that is why it is working with the choke on.
"THE KING OF BLING"!
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mrlmd
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Re: FPL won't runwithout choke

Post by mrlmd » Sun Dec 29, 2019 5:25 pm

Right now there is no filter inside the fuel tank. I haven't replaced that yet and is the only part left I need to get. The banjo filter is clean, there is free flow of fuel into the bowl, the tickler works, and you know how long these things can run even with the petcock turned off just on the fuel in the bowl. The engine runs great, just cannot move the choke shutter at all or it will die.
So it can only run on a rich mixture?
Does the change in needle in the carb to run on 25:1 instead of 10:1 mess things up? It makes no difference if I raise or lower it a turn or two, it still dies if I open the choke.

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Charles uk
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Re: FPL won't runwithout choke

Post by Charles uk » Sun Dec 29, 2019 8:07 pm

So the FPL is running a Villiers carb, what size is the throat diameter in your carb?

Try running it with the 10:1 needle but with 20:1 & 25:1 fuel, & let us know how you get on.

There should be a 10 thou " paper gasket between the top of the drive shaft & the bottom of the crankcase.

A little more lubrication won't harm the World too much & we don't know how much work your 40+ did in it's previous life.
Make it idiot proof and someone will make a better idiot.

mrlmd
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Re: FPL won't runwithout choke

Post by mrlmd » Sun Dec 29, 2019 11:19 pm

Thanks. I was actually thinking of trying that, putting the old needle back in, but I was wondering what that would do to the engine which was designed for a 10:1 mixture. What does the change in needle do, make it a richer mixture? More fuel delivery? Why did BS originally spec this out as a 10:1 and what happens if it's now run on 25:1, a lessor oil mix? If it will run OK on the old needle and going to 25:1, then why do you have to change the needle to accomplish this change? So many questions.
I will let you know what happens after I switch back to the old needle, just hoping the motor will tolerate the 25:1 mix and not die an early death.

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Re: FPL won't runwithout choke

Post by Collector Inspector » Mon Dec 30, 2019 5:42 am

Hi Mark

Did you forget the washer under the centre piece/jet holder?

If missing or not sealing there will be running issues.

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mrlmd
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Re: FPL won't runwithout choke

Post by mrlmd » Mon Dec 30, 2019 6:40 pm

I didn't notice one fall out when I took the center piece out to clean the side hole air vent, so it must still be in there. But I may take it apart again to take a look just to be sure.

mrlmd
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Re: FPL won't runwithout choke

Post by mrlmd » Mon Dec 30, 2019 8:40 pm

Charles - I followed your suggestion and replaced the new needle I got from John at SOS, meant to replace my #3 to allow running on 25:1 mix. It's supposed to be a #2 but there was no number stamped on the needle he sent me, altho it was in a packet said for the 25:1 conversion. With that needle he sent I could not get my engine to start today no matter the position, 3 turns up or 3 turns down. But after I replaced it with the original #3 meant for the 10:1 mix, the motor started on the first pull and runs fantastically well, without the choke too, even down to the really slow idle, and as usually happens, is hard to kill but the choke and fiddling with the throttle cable to make sure the slide is all the way down, will shut it off. So it looks like the problem is solved, but there's a few questions left.
If it stills runs on the 25:1 mix, why the necessity or recommendation to change the needle?
Is there going to be any short-term or long-term damage to the engine using the 25:1 mix when BS says it was designed for 10:1? Am I still getting enough lube into it? Should I compromise a little and go to 20:1, for both this FPL and my other EFPC, as I only really want to have one fuel mix for both?
This engine has had the cylinder block and pistons replaced with used ones that look very little used or worn, and has new rings. The connecting rod and crankshaft are the originals. But like I said it runs great right now, I'm just wondering about any long-term effects on wear.
Thanks.

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Re: FPL won't runwithout choke

Post by geofflena » Mon Dec 30, 2019 10:45 pm

Should be ok - mix was to do with the size of the main bearings in crankcase. From year 68 they were longer - hence less oil needed to make a good seal on a plain bearing. So - as long as yours are the longer ones - 25:1 will be fine.
Could be an issue with the centre tube - rather than the needle ? They are hard to remove and can have had a bashing over the years ! Might be worth trying a spare centre tube ?
If its running fine ok - but these things sort of bug you until you sort out why !

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Charles uk
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Re: FPL won't runwithout choke

Post by Charles uk » Tue Dec 31, 2019 12:37 am

The needle change was due to the difference in fuel viscosity between 10 & 25:1, the 25:1 needle is slightly larger than the 10:1.

When any plain bearing 2-stroke is over 35 years old a little TLC in the way of extra lubrication couldn't hurt.

There has only ever been one main bearing part number for each of the 40 series crankcase main bearings, though I was told by an Seagull employee that they were reamed 0.0003" (3 tenths of a thou) smaller than the earlier 10:1 mains.
Make it idiot proof and someone will make a better idiot.

mrlmd
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Re: FPL won't runwithout choke

Post by mrlmd » Tue Dec 31, 2019 2:00 am

From looking at the center tube when I gently hammered it out, I don't think this was ever removed or even touched before, so that's probably not an issue.
I assume the main bearing is fine because I could easily spin the engine by hand without the plug in and there's no resistance or scraping noises. If I continue to use the 25 or go down to 20:1 mix with the #3 needle, I guess time will tell how much bearing wear I get.
I'll have to see if the EFPC will run well on that mix, otherwise I probably will just leave things as is, and as long as they both run, leave them that way.
What I don't understand, if the center tube and jet is the same size for both the '80 EFPC and the '76 FPL, then why don't they both run well with the #3 needle, and why the FPL needs the #2 instead. There must be a difference in the size jets for that to happen.
Last edited by mrlmd on Tue Dec 31, 2019 10:46 pm, edited 1 time in total.

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Re: FPL won't runwithout choke

Post by Collector Inspector » Tue Dec 31, 2019 9:40 am

mrlmd wrote:
Tue Dec 31, 2019 2:00 am
From looking at the center tube when I gently hammered it out, I don't think this was ever removed or even touched before, so that's probably not an issue.

Was there a thin fibre washer or not?

Being slightly difficult to remove in no way means that that it has never been touched.

Just trying to help with this "avenue of diagnostic" is all...

Safe new year to all Aye.

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mrlmd
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Re: FPL won't runwithout choke

Post by mrlmd » Tue Dec 31, 2019 11:01 pm

CI- I haven't opened it up again and taken the center jet out as it's running so well now I hate to disturb it to look inside again. How thick is that washer? Could that 1mm height difference, if it's missing, have that much of an effect? Turning the screw in and lowering the needle should have made up for that. There was nothing that dropped out when I knocked the jet tube loose and pulled it out, and judging by the looks of it when I took it apart, I really don't think anyone had been in there before but since I don't know the history of the engine before I got it, I'll never know for sure unless I take another look. Like I said, it's running so well now I really don't want to do that, and in the long run, it makes no difference at this point other than academic interest. But thanks for the suggestion and if I ever do open it up again, I'll let you know what I find.

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Re: FPL won't runwithout choke

Post by Chris B » Sat Jan 04, 2020 3:33 pm

Interesting thread, this one.

It seems clear that the engine is demanding more fuel than the carburettor is willing to supply. Maybe I've got this wrong, but as I understand it, it will run on 25:1 but with the wrong needle. So the problem looks like a weak mixture and the issue must therefore lie somewhere in the carburettor or elsewhere in the fuel system - right?

Well, possibly but not necessarily.

A faulty ignition system causing sub-optimal combustion, can produce misleading symptoms that bear all the hallmarks of a weak mixture. Completely different problems but the similarity of the symptoms can - and frequently will - lead the troubleshooter down the wrong path in his quest for the cause and a remedy.

Adjustments at the carburettor can sometimes be persuaded to compensate - at least to some degree - for an ignition fault, and a departure from the recommended settings might get the engine running tolerably well. But the required departure from the standard settings will probably seem a bit puzzling. That's because the underlying problem is still alive and kicking elsewhere. In such cases, changing the carb setup hasn't fixed the problem - it's just hidden it under a sticking plaster.

The OP has told us that the engine was lying immersed in salt water for a lengthy period of time. Given the symptoms he's described, that really should ring alarm bells. Before worrying any more about the carburettor, I'd be inclined to completely strip down the ignition system of that particular engine, give it a very thorough overhaul, and replace any components that can't be verified as being 100% okay.

It's been said before that 90% of the mysterious problems blamed on carburettors are due to faulty ignition systems! I don't know about the percentage but I do know that it happens. And while nobody knows if that's definitely the case here, given the symptoms described by the OP and the engine's recent history, I'd be inclined to bear it in mind.

The ignition and fuel systems depend closely on each other to produce the required result, and all too often, when an ignition system isn't running correctly, the symptoms will result in the carburettor getting the blame and becoming the focus of attention. Having looked at the OP's posts again, I do feel this might be a situation where the ignition system might deserve close scrutiny. At the very least it would rule out the ignition system as the underlying cause of symptoms which almost inevitably lead to a misdiagnosis of too lean a mixture.

Keep in mind the fact that seeing a spark at the plug simply means there's life in the ignition system. It does NOT necessarily mean the ignition system is operating correctly.

Of course I may easily be wrong with some or all of the above but it's just a thought...

By the way and going off at a tangent, apart from other possibilities which include a slack / slightly leaky main bearing (it won't necessarily be noisy when you turn the engine over), you might want to double check that you've got an airtight join between the carburettor and cylinder block inlet port.

Sorry this post is so lengthy - I just didn't want to miss out anything!

C

mrlmd
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Re: FPL won't runwithout choke

Post by mrlmd » Sat Jan 04, 2020 5:40 pm

The coil resistance measures as specified at 4600 ohms, the HT lead is good, the plug is new, there is an incredible bright blue-white spark at both the points and the plug, and after getting the fuel mix right, it starts immediately and runs perfectly, even at a really slow idle, so I can't see that the ignition is any problem at all and I don't see how changing any component of it can make it run better.
What John at SOS last suggested to me is that there still may be a minor problem with fuel delivery as it won't run on the new #2 needle he sent me, with possibly a blockage at the lower end of the air line in the center tube containing the jet. As far as I can tell, I did clean this all out and can blow air and carb cleaner through it easily, but one of these days I may take it apart again. Right now, with the original #3 needle in place (which was meant for a 10:1 mix) it runs perfectly on the 25"1 mix.
I also have no air leak at the carb-block joint as tested by spraying carb fluid or WD40 on it while running, so that is not a problem leaning it out.

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