GFP1036FF6 Forty Plus with Bing carb.

[Porthandbuoy]

I was given this engine a couple of days ago. Why? Because I mess about in boats and have a couple of dingies to get me out to my yacht on its mooring.
This engine spent at least the 30 years propelling two elderly gentlemen around Loch Awe in a heavy 12' mock-clinker grp dinghy; stopping only for a beer and to cast a lure into the water. When the engine packed up 4 years ago they splashed out and bought a modern 4hp 4-stroke and the Seagull was pensioned off.
The engine doesn't seem to bad to be fair. The tanks is dented and lacking paint, but it's still half full of old 2-stroke mix. The prop has a few dents and dings thanks to the stony foreshore of Loch Awe. There's plenty compression when I compare it to my Mariner 2hp 2-stroke. The plug came out easily, well sooted up but with only a 10 thou gap. I opened it up to 25 thou and there is a nice fat spark when I pull the starter cord. The prop spun as well so the top is connected to the bottom; always a plus.
The carburettor looks to be the only questionable bit. It's a Bing carb, so good for a 25:1 mix. The cowl is missing and the cable just lifts out of the top.
First things first though. Drain the tank, a damn good clean and then see if I can fix the carb and get it started.

https://www.dropbox.com/scl/fi/4qcqcnlh ... v1bqh&dl=0

https://www.dropbox.com/scl/fi/8w20pjxm ... 5mx35&dl=0

[Porthandbuoy]

Fuel tank drained. It had a nice coating of thick, black gunge. Poured in 1/2 litre of Thinners #3, which is a pretty aggresive solvent, and shook it around for 5 minutes. Removed the fuel tap and poured it out. Tank now clean. I expected the gauze filter on the tap to be blocked but it came out clean. Put it back in with the original washer.

The sliding barrel, or sleeve, which holds the needle in the carb was jammed solid in the closed position. I suspect this was why the previous owners gave up on it. I got it out by inserting a short length of throttle cable into the barrel, taking a wrap around my fist and hauling. The needle was a bit rusty so I cleaned it up with 0000 grade wire wool. I gave the barrel and the carb body the same wire wool treatment then lapped them with brasso until they were a nice sliding fit. Good practice? I don't know, but the needle now slides up and down with ease.

There is another fuel filter on the side of the Bing carb where the fuel enters. It was completely blinded by the fine sludge that got past the tank filter. It's a fine plastic mesh so I cleaned it with hot soapy water and a fine brush rather than Thinners #3 which might have dissolved it.

Unscrewed the plastic bowl underneath the carb. It was 1/2 full of even finer sludge! Cleaned it with hot soapy water and a fine brush. I do wonder if these plastic components are compatible with modern bio-laden fuels. FWIW I run all my other 2-stroke toys on premium fuel as it has less methanol than the cheaper stuff.

Now the moment of truth! I put everything back together, poured a pint of 25:1 mix into the tank (a bit richer to be honest as the engine hasn't run for years, probably nearer 20:1) set the plug gap to 20 thou and pulled the fuel tap on. Tickled the carb until fuel dripped (well, dripped a bit more), closed the choke, wrapped the cord around the starter, and pulled, pulled again, and pulled again. It started, ran, and responded to the throttle. I took the choke off and rev'd it up and down. The engine ticked over nicely in air, something I doubt it will do in water. Ran it until the head was warm to the touch, stopped it and it started first time without any choke.

That was just a dry run. I still need to run it in my test barrel once I've serviced the bottom end, checked the points gap, fitted a new plug and, maybe, a new needle for the carb.

[Porthandbuoy]

Bit of a setback today.

Took the prop off so I could run the engine in my test tank (a plastic dustbin). It started 1st pull and roared into life and at first I thought all was well. Then I noticed there was only a dribble of water coming out of the tell-tale hole in the block. I increased the revs but the dribble didn't increase to a pour.
I stopped the engine and tried backflushing the cooling water circuit. Nothing but water came out of the bottom of the leg. Ran the engine again to see if perhaps the dribble was enough. No it wasn't. After a few minutes the water was too hot to touch and was starting to turn to steam.

Back in the shed I got the bottom end off so I could access the water pump. Managed to shear the bolt in the bottom end clamp. I found the grit seal behind the prop cut to ribbons with a lot of nylon monofilament wrapped around the shaft. There were also monofilament threads sticking out of the cooling water intake slots. Tried pulling them free but they just snapped no matter what direction I turned the square drive shaft. I suspect the rotor is wrapped in monofilament and/or damaged.

With the bottom end off I managed to remove one of the machine screws securing the top of the water pump housing. That took a lot of heat and a lot of persuasion with an impact wrench. Damned if I can remove the one in the centre between the clamp and the exhaust spigot though. Any tips on how to remove this would be appreciated.

I'll need to drill out the broken bolt in the bottom end clamp. If easy-outs don't work I may drill and tap it for a metric bolt. On the plus side the crown and pinion gears are in perfect condition. The oil/water emulsion in the gearbox was smooth and creamy with no trace of grit or metal particles.

Things to buy (so far)
1) Needle for carb.
2) Set of taps to clean up the threads in the bottom end.
3) New machine screws for bottom end.
4) Grit seal.

[Porthandbuoy]

Managed to drill out and tap the bottom clamp for an 8mm bolt. Took longer to make up a clamp jig for my pillar drill than to do the job.

That centre bolt! I ordered a longer slotted screwdriver bit for my impact driver so I could get it down in between the clamp and the exhaust. I then applied some heat, okay a lot of heat, to the threaded part of the bottom casting. I then alternated left then right using the impact driver. Eventually it started to undo and I got it out. The head of the machine screw is wrecked of course,

The impeller/rotor is okay (despite the heat)
but the gallery between the impellor/rotor and the tube that take the water up to the power head was choked with a mixture of monofilament and carbon. I had to dig it out with a screwdriver. No way would it have blown clear.
TIP: A garden sprayer, the sort used to spray weedkiller, the plastic tube is the same diameter as the cooling water tube. Unscrew the plastic tube, screw on the cooling water pipe and pump a few litres of hot water through the power head. Loch Awe, where this engine had been used for most of its life, is fresh water, so when I flushed it the water came out as clean as it went in.

The drive tube chrome is in a sorry state, but as I'm not planning to restore this engine to 'as new' I might just paint it. The aluminium exhaust tube is in perfect condition. I've straightened out the dings in the propeller blades. The propeller and the bottom end castings seem to have been painted with a metallic silver paint. A lot of it is missing, and as I'll be using the engine in salt water I'll strip what paint is left and re-apply.

All that's left to do now is send John an email for a few bits and pieces to finish the job.

[Porthandbuoy]

New problem.

Does the machine screw circled below go into a locating hole in the bronze bush? If so, I have a problem. I removed the driveshaft, as advised on this forum, by inserting a long rod down the driveshaft, holding the driveshaf and giving the rod a good clout. It actually took several clouts.
Problem is the machine screw 'bottoms out' long before it could bring any pressure to bear on the bell housing. As I removed the driveshaft with the gearbox in pieces it looks like I may have pushed the bronze bearing down the alloy housing.

https://www.dropbox.com/scl/fi/znas8wwj ... bipby&dl=0

[Charles uk]

Yes it does.
You'll notice the top screw has a domed end, that's fits in the dimple in the pinion bush & holds it in place at the correct height & keeps the pinion gear correctly meshed with the crown wheel on the prop shaft.

[Porthandbuoy]

Thanks Charles. Looks like I'll have to heat and expand the casting and somehow persuade the pinion back into position.

Looks like I'm the better idiot in your signature line.

Before Lunch: Got the pinion and bush out by heating the casting and slamming it down on the worktop a few times. I'll heat the casting, freeze the bush/pinion and hopefully it'll slide back in and I'll be able to align the hole before it all locks up.

TIP: For anyone else removing the drive shaft from the gearbox. Do it before you dismantle the gearbox!

After Lunch: Cleaned up the bush and pinion. Did not separate them. Put them in the freezer
Popped the bottom casting in the Aga top oven for half an hour. Brought the two together and the bush slid into the casting with very little coaxing. Took care not to overshoot and when I could see the hole in the bush through the threaded hole in the casting I screwed in the bolt with the tapered end. That finished the allignment of the bush/pinion so I can get on with reassembling the gearbox.

[Porthandbuoy]

It's alive! It's alive!

With the new machine screws from John I started to reassemble the engine. First I had to clean up the threads in the castings. Easy enough with the correct tap, inherited I think from my grandfather. I had to shorten the one that goes into the locating hole in the pinion bush and grind a slight point on it. Too long and it would push against the bottom of the hole and make the pinion shaft bind. Yes, I had to take the damn thing out again and sort it.

Couldn't find a Champion D19 locally but was able to get the NGK AB6 equivalent. Put everything back together except the prop and gave it a test run in the barrel. It started 3rd or 4th pull and water came pouring out of the tell-tale when the revs taken above idle. Put the prop on and tried again. No water this time, almost certainly because the water in the barrel was so aerated.

Time to try it out on my 8' dinghy. Again, 3 or 4 pulls on the cord before it started cold and, after a brief run, hot. I increased the plug gap to 30 thou and when warm it started 1st pull. Still to see if it starts better when cold. Water comes out of the tell-tale when the throttle is opened a touch and the dinghy scoots along nicely at around half throttle.

The engine dies when I open the throttle fully. Looks like fuel starvation as closing the throttle halfway brings it back to life. Tried pushing the priming button down to flood the carb but it didn't make any difference. 2/3 throttle seems to be the max at the moment. Could be a couple of things:
1) Blocked filter(s)? Don't think so as I cleaned them pretty thoroughly.
2) Needle in the carb? It's a bit rusty and pitted. I cleaned it with very fine wire wool, removing the rust and leaving the pits.
3) Needle installed in wrong groove? I never removed the needle from the sleeve, so that's a possibility. Is there more than one groove? I don't know.
4) Throttle cable? Mine is fully screwed home into the top of the carb and there is no locknut. Could be the wrong length cable. The sheath is also damaged and the engine revs change when I turn the tiller or lift it up or down
5) Throttle lever? Could be the wrong one with more travel than the carb can accomodate.
6) And, possibly the most likely, is the carb vertical? At the moment it is aligned parallel to the drive shaft/exhaust. Could be I need to adjust it taking into account the transom rake. Wrong angle will affect the level in the bowl, but that's a job for another day.

I made a cowl for the carb from an aerosol cap. Melted a few holes in it and, although a pretty tight fit, I locked it in place with a drop of superglue.
https://www.dropbox.com/scl/fi/2n6pldwd ... 9dfbc&dl=0

https://youtu.be/8TSHzLmBEzI