BIS engine rebuild

[Guldbergdk]

Pulled the engine from the 126 for a winter rebuild. It was leaking oil which turned out to be from the craftshaft bearings being shot.

Here is a stack of pictures. Didnt take to many during the actual rebulld but every thing have been taken apart sand/glass blasted and some parts painted.

[Guldbergdk]

Did some preliminary testing running the engine on the bench. Started pretty easy. Now I need to fine tune the timing.

Question: I screwed the idle mix screw (the one on the bottom of the carb) all the way in, but the I think its still running to saturated (opposite of lean?). The exhaust is all white.

What is causing white exhaust?

Anybody have a good guide to tuning a carb? One better than in the manual.

[Njkip]

If I'm not mistaken white exhaust gases is generally associated with burning oil.....😳

[126blackbird]

White smoke is normally water, blue smoke is oil

[Guldbergdk]

Used to drive offroad. When wading to deep water would enter the air intake causing a lot of white smoke. Might be the head gasket then. I would just assume that gas would leak into the coolant and not the other way around.

[Pete126]

If the inside/internal surface of the exhaust pipe is a white colour this could mean the engine is running a  weak mixture, if you mean the exhaust gases, when you start the engine is expelling water vapour/exhaust this is normal if the engine is cold or damp but should run clean when the engine is up to operating temperature (when all the condensation has dried out from the internals engine and exhaust)

[Guldbergdk]

I’ll try and run it for some time, it heats up pretty quickly. I do remember that I had to top of the coolant a couple of times more than I like. Fingers crossed.

The cylinder and top have seen better days, but I would hate having to buy a new of either.

[Pete126]

If you're running the engine on the test bed you could have airlocks in the pipes, try squeezing them when the engine running, the best way to check if the head gasket is still leaking is to buy a cheap test kit off eBay

[Guldbergdk]

Thats an airlock for fermenting:) Got some of those

[Pete126]

It's the Chemical you need
https://www.ebay.co.uk/itm/123735248113