Saving Old Seagulls

I would be grateful for any feedback on the following problem.

I have a 40 long shaft with clutch FPCL 599BB8

The problem is that the engine wont start (when cold) on the rope. I can start it using a drill on the flywheel nut when it will fire after 5 or 6 seconds.(never straight away !) Then it will run quite happily and respond correctly to the throttle with no misfiring. After the engine is warm it will then start on first pull on the rope.

As far as I can see the engine is original and is in good condition for its age. It does not smoke much when running and sounds healthy.

I have tried all the following
1. Fresh fuel
2. Cleaned out the entire fuel system (twice). This included a complete strip down of the carb
3. Tried a second carb
4. Flooding the engine by placing a cloth over the air intake
5. Replaced the ignition lead including both connectors.
6. Cleaned spark plug several times
7. Replaced spark plug
8. Checked and cleaned points several times.
9. Replaced magneto components
10. Stripped engine and replaced gaskets(Not cylinder head)
11. Ensured that there are no hair cracks in block
12. Checked depth of water in my test tank.
13. Made sure the holes in the exhaust aren’t blocked
14. Made sure the ignition base plate is not loose and is correctly located.

I haven’t tried
1. Replacing flywheel (no spare)
2. Checking quality of spark (no equipment)
3. Testing compression (no equipment)

The clue seems to be that it won’t start straight away using a drill, which leads me to suspect that oil in the fuel eventually seals the engine somewhere but to the best of my belief I have eradicated that as the source of the problem. However as I am unable to test the compression I wondered if wear of the piston/barrel/rings could be the cause. Does anyone know if general wear will have this effect?

Or does anyone have any other suggestions ?

All feedback gratefully received !

PS I am not always able to check my email regularly so apologise if I appear to be ignoring you.

Thank you

Without a compression tester it's hard to test, can you feel compression resistance when turning it over by hand when cold, you should easily be able to feel the compression by hand.
But your symptoms sound like rings and from the list of what you have already done, a set of rings seems to be the next logical step.

When you try to start it, it is out of gear, right?

it will make no difference if it is in or out of gear, what is your starting procedure, are you flooding it with the tickler on the carb and using full throttle and full choke, as they need this to start cold, I have used old well worn seagulls with worn rings and they still start easily.

Make sure everything is tight. Crankcase nuts--Cyl to crankcase nuts--Cyl head bolts--Carb and mounting clamp. Look further. But make sure everything is tight.

Thanks for the replies

To answer your suggestions

The compression feels ok - ive started many seagulls over the years and this one feels like all the others.

I have double checked all the nuts for tightness

Yes its out of gear

I think I tried just about every combination of throttle and choke possible, including super flooding (Should have put this in my original posting)
As a matter of interest I dont think it has ever fired once when starting from cold on the rope.

I think I will see if I can find a compression tester before dismantling the engine again

I did have one last thought. Is it possible that someone has changed any part of the magneto (including the bottom plate) and replaced with unsuitable parts which has affected the timing? I know that some flywheels off different models look similar but I always thought that they would not fit. How can I identify if these components (not just the magneto itself) are right for my engine.?

Again thanks to all for the advice

Fitting a Century crankshaft to a 40 series motor could in some cases cause this problem.

I had a mower like your seagull many years ago and eventually put it down to someone putting grease on the contact points shaft. After removing and deep cleaning the points in petrol, and refitting with no lubrication it started and run a treat.

I have purchased a compression tester so will see what that shows on Sunday.!

Charlesuk ..... are you able to tell me how to identify different crankshafts?? I assume the length differs which would mean that the engine is not firing at the optimum time. Are they marked in some way?

Many thanks

No they are not marked.

But if you hang a 40 series crank assembly from the piston, crown uppermost, the woodruff key notch is about 10.30 on the crankshaft, whereas the century notch is about 7.30.

More often than not, 40 series cranks don't have the extra balance weights on the crankshaft flywheels & are of lighter sections.

Hay Charles you can borrow a timing light and check timing by marking the flywheel at top dead center . Feel the piston with a pencil rock over and get a feel put a tape mark on the gas tank and one on the flywheel hook the timing light to the spark lead and you will see if the timing is way off !!! But if it runs good once started its probably O K . Take an old spark plug and cut the tang off. With an easy pull on the rope it should jump spark to the side 1/8 to 3/16 inch or 2 to 3 mms this simple tool works on cars lawn mowers and seagulls not on BIRDS ! Hope this helps ! VIC

Well .....I have checked the compression on the 40 and the dial is steady at "Naff all", so Ill drop John an email for some new rings !!!!

Charles UK thanks for the info on the con rod .... Ill check that as well just in case.

Ill post a reply of the outcome of the new rings in a few days(probably after next weekend)

Thanks everyone