6 Hp - Can bad leafs keep it from starting?

[BigB9000]

Ive been working on a 1972 6 HP for awhile.

Sand-blasted, cleaned, and painted everything but the powerhead. Rebuilt / resealed, lower, new water pump, lower crankcase seal, fuel pump, fuel line, spark plugs, coils, points, condensers, wires, boots, carb kit, even install a hard to find propeller guard, and tiller handle shift kit on it.
Only thing I didn't do is pull the intake manifold have a look.
Timing was set with a timing fixture, spark is great.

I usually have great luck with these old engines, apparently not this one.

It wont start.
Not even a hiccup of starting.
Just pull pull pull.

Dumped some premix into the carb, nothing.
Got frustrated, pulled the plugs, and dumped some into the cylinders.
Fires for a split second and nothing.

Pulled the carb off, and dumped fuel into the intake manifold, nothing.

Pulled the powerhead back off, pulled the intake, and saw badly corroded, stuck open leaf valves (both)
Would this cause it not to start? Even slightly?

You would think as not all engines even have leafs if would have done something, not absolutely nothing.

With the intake off, I could see the crankshaft. I have a little corrosion starting on the rod caps, and spotting on the crank itself.
Is this cause for concern, or will it probably just burn itself clean?

Compression was 70 (or 80) cold and dry. Good enough to run.

I was going to buy new leafs and gaskets and call it a day.
Problem is they are $16 each (x2) now I'm thinking about borrowing them from a donor engine.
Powerhead gasket is $9 each, intake manifold gaskets I could reuse? New they are $13 and $8

Before wasting money, I figured I would get some options on what to do.

 

[fhhuber]

Bad reed valves will definitely keep a 2-stroke from running.

 

[Chrisravosa36]

Agreed. Pull em out and really inspect them, get new ones.

 

[Tim Frank]

Pulled the powerhead back off, pulled the intake, and saw badly corroded, stuck open leaf valves (both)
Would this cause it not to start? Even slightly?

You would think as not all engines even have leafs if would have done something, not absolutely nothing.

In a sense, the leaf valves do the same as the intake and exhaust valves on a 4-banger.
Imagine a condition where all valves stay open all the time.
What would you expect?

If there is corrosion on the rod caps, there may well be corrosion UNDER them. That is a potential landmine.

Up to you whether you do a proper investigation or just install new leaves and cross your fingers that it does not self-destruct.

 

[F_R]

Yeah, the comment about finding corrosion in the reeds and crankcase concerns me. Now that you have done all that work and expense, it may be in vain. Do a proper evaluation of that powerhead before spending more money. You may need to pull it down for a looksee. Can't see it from here.

 

[HighTrim]

I would probably open it up as well. Worst case scenario, if that rods and such are fine, at least you get a chance to reseal the crank halves to knock that off your list of why it wont start, which is what I was thinking, before you mentioned the reeds.

 

[gm280]

If you are at this point now, take the power head off, open it up, inspect all the main and rod bearings and clean up everything if it looks okay. Make sure you oil them when reassembling. Start up is hard on dry bearings and such. But also check the bore and piston(s). The bore may need honed and new rings for the piston(s). The reed valves can cause the engine not to start and run. If you can't clean them up where they close on their own, replace them. Once you finish this stage of the engine, I bet it will run and run very well. JMHO!