Removal of dome nut

[Taspiper]

Didn't think of modifying one and just went down the road of a NKG plug equivalent which have the smaller porcelain.
I've had many problems with Champion plugs from new over the years that I don't trust them anymore.

[websterj]

Not gonna use the Champions. Used instead the old (original?) NGK. It worked.
Backflushed the water pump, took a chance and cranked with fingers crossed, and hallelujah, it ran solid.

So my Nova Scotia bro-in-law is real happy. Took the trank off for traveling, found sediment, and a piece of brass in it (dunno what that might be) - looks like someone sometime put new studs in the tank to attach to engine - they have different thread patterns, oh well.

Think we saw some water flowing into the telltale for water pump but hard to tell with all the water boiling out of the garbage can.

I think it's a good engine - now I want one for my old aluminum johnboat. Better than an electric and more fun.

Took off the carb for traveling - he will clean all that up before reinstalling up ther.

A very good day.

Thanks guys!! Could not have done it without this forum - not home-free yet, but very close.

Jim

[andrew]

So I’ve got a dome nut, mark II ignition, that just doesn’t want to come off. Have tried most everything I can think of to keep the flywheel from turning while giving the spanner a good whack. Last try was getting flywheel in a tight bench vise (with wood blocks) and still no luck.

Tried a small amount of heat but didn’t want to melt anything so couldn’t give it much.

Any recommendations? I’m sure someone has crossed this bridge before!

Thanks

[Gannet]

Hi Andrew,
I have never had any difficulty with undoing the dome flywheel nut, so have no experience of what to do.
But what about drilling a hole in the top of the nut so that you could introduce some suitable freeing agent into the threads, as it is possible that corrosion could be the problem.
It is also possible that a thread locking compound has been unwisely used in the past. That of course will require heat to break down the compound...……….


Good luck!

Jeremy

[Hugz]

I think you will have to accept that the wipac sheave is going to get heat damaged and put some serious heat on the nut. The sheave is readily available. A wet rag may suffice to keep it from too much damage. Another thought is that there is a tool called a nut cracker which does as the name implies. Whether it will work on a nut this size l do not know. Again spare nuts in our community are common place. Generally I've found that if the thread is damged it is usially the nut thread and the crank thread stays intact. Good luck. Removing the flywheel maybe just as exciting too. Getting lubrication on this thread is going to be hard. Drilling oil holes in nut? Personally l would be going with heat and wet rag or spray water bottle or non flamable can of 'cold spray'. The coil and condensor is sufficiently far enough away that they shouldn't be affected by heat to nut. Good luck.

[Hugz]

Interesting that Jeremy and l both thought of drilling nut to lubricate thread.... consensus of opinion??

[Charles uk]

Mk 2 flywheels are quite brittle so handle with care.

Did you try to start by using the electric drill silly idea? as that can over tighten the flywheel nut!

I've locked flywheels by putting the piston just after TDC, then filling the cylinder with fuel mix & replace the spark plug, a sharp tap with a medium weight hammer should do it.

Not too hard as you could damage the con rod!

[andrew]

Thanks all for the suggestions! I ended up getting it off with brute force; was originally worried about cracking the flywheel in the vise but decided to really crank it in there and give it as much heat as I could. Plastic started to melt slightly around the washer but I had a couple old spares. Had to reset it in the vise probably 10 times before it finally came loose. Loads of rust in there, looks like the nut was also a bit fused to the washer which didn't help!

[Oyster 49]

That's certainly well corroded, I'd suggest wire brushing both threads and copper grease when putting it back together.

[Rob Ripley]

while we are talking about dome nuts ..... I've noticed there are several shapes. Is it related to various models or years ?

[geofflena]

HA - I search recently for posts on magneto coils/points - trying to trace a non sparking Suzuki dt2 fault ( I do have many seagulls as well ) - I end up finding my own post - so am still confused - until today.

Yes - I now have a very healthy sparking DT2 - AND - my points appear to show continuity to ground base - open or closed.

The reason in the first place I had the flywheel off is I thought i had something dead in there.
Unlike the seagull - the DT2 has a moveable baseplate - so basic timing can be messed up when moving it.

After much more searching today - after more confusion when reading an old Suzuik shop manual that says I can test the points gap opening with a ohm meter set to continuity ? - ie from stop wire - to ground ?. They are wrong - you can't - not easily at any rate.

There is a good bit of info on the Frost website - who make a special ignition timing meter especially for these type of magnetos.They make the point its hard to test points opening electronically with these magneto types - hence their special meter.

The problem - if you look carefully at a wiring diagram is one side of points is connected to ground - one side to ground through the primary coil - which as said is only 0.5 ohm - so is hard to descern from continuity.

I now find myself back again to my original source - ha. Its a small world - but have at last got my head around the issue.

Just to keep on track - the emergency repair to Suzuki interupted my stripdown of my latest aquired seagull - a tidy little 40 plus.
Came apart ok'ish - but had to slice through the gearcase top gasket sideways to chop the top middle cheese head. Thankfully the bitter end yielded to a pilot hole, extractor and heat !
Not yet checked that one for spark !