Would be eerie if the same mechanic @rusty360. What suburb is your mechanic?

Mine was smoky on restart as well. Wonder is same issue. They said resolved so keen to hear your outcome and share mine tomorrow. The tropical cyclone hasn't made it crazy but will be a bumpy session. i am going to put line in since might as well!

A smoky 4 stroke is a problem. Are you sure it is smoke and not just condensation? There are many people that will tell you about the advantages of running engines on a higher octane fuel than that specified. Do NOT take advice from those people.

Been on a raod trip just catching up now.

Couple things above
I mentioned the bulb not filling when i went to pick up and this was replaced on the spot. Apparently you should hold it vertical to use - who new?!)

The buld hast to be mounted vertical.. even if a little off (as mine is , guilty) the non return ball bearings dont sit in the seats and the fuel slowly (espec on carbs) leaks back. So you maybe anchored up for 1/2  or 1hr plus  go to fire up and doesn't quite 'catch ' couple good pumps and fires up

A mention dirty plugs..
An engine 2S or other wise that timing is set Correctly.. (and leave that to proper workshops with the proper gear, including test tanks and the testing props so can load the engine correctly) And the correct 91 octane used will run for yrs without fouling up.
What happens thu is the gaps increase, more current to drivwe the healthy sopark, more load on coils etc, and bad spark issues arise.
 Bad spark .. dirty plugs..
Dirty plugs are a symptom of something else wrong


Your mechanic sounds dodgy but hopefully he has it fixed this time.

And yep I keep coming back to that...
Doesn't mean the workshop or owner is, but a doggy person on the tools is not  uncommon.

 I have had U bolts installed in a very reputable workshop.. 20 to 25 lb torgue.
I walked back into the workshop, handed a cracked fuel hose to the workshop manager after a 'service'
A charging system stuffed cause the same person short cutted, by test running engine and thought a good idea multi task,to re grease the battery terminals.

The workshop quietly dealt with the matter.

And that person has been thru at least 3 other reputable workshops since.....that I know of.

Agreed and makes sense @Mattoo.

i'll PM you rusty360.

A 4 stroke running really rich will make grey smoke, too much choke?
Shouldn't need a lot of choke at all after a 10 seconds or so of running.

I dont think there are many around who know what a leak down test is , or how to do it, these days... let alone how to find compression stroke.

Probably more than you may think Steps.

 Or not.. been around far too many vintage and rod clubs/ shows/events over recent yrs.. leak down often gets a blank look..

And old school is not "better" its just being able to tdc on firing stroke without a piston stop...dont think there are many now who know what that is either..let alone have one in their home workshop.

Refer back to Durbans post..
Funny how know one mentioned dont need TDC for leak down.. on the other hand having such a fault, good practice is to find TDC while at it, by piston position, establish timing marks ,  are actually correct, no slop in key ways, perished rubbers in balances etc....

Also an old school trick.. is it worn valve guides or rings?
Mark the plugs as they sit in the head... pull the plug, carbon on the bottom, rings , carbon on the top valves

And if doing leak down.. dont do what have seen done so many times.. grab the compression tester, bring up the pressure and pressure stays the same...because still got the valve in the end of the gauge...

Smoke... 4S... timing, mixture , rings/ valve seals (espec if on initial fire up)often a combo of the above.

This motor is a 2S merc so I don’t see where all the talk above has any relevance.