Mercury 2.2hp two-stroke timing

Rum Run

Rum Run

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Hello all, I have a question regarding a Mercury 2.2hp two-stroke outboard which will not start.
The spark is good, fuel is flowing ok and the carburettor is clean. However it refuses to start, just occasionally kicking back and trying to pull the pull start handle out of my hand.
Looking at the points the gap measures right, but when probing through the spark plug hole it seems like the points start to open just after bottom dead centre which is not what I expected at all! So far as I know the points gap is the only timing adjustment-is that right? If so, what am I missing .......

Thanks in advance
Brian
PS the last ditch backup Seagull Featherweight which hasn't been used for two years and has three year old fuel in it started second pull.
 
The first thing I always do is chuck a few mls of 2T mixture into the air intake and pull the cord.

If the engine starts and then stops after a few seconds, you will know it's a fuel issue. If it doesn't fire at all, you will know that it's electrical. :)

Richard
 
RichardS said:
The first thing I always do is chuck a few mls of 2T mixture into the air intake and pull the cord.

If the engine starts and then stops after a few seconds, you will know it's a fuel issue. If it doesn't fire at all, you will know that it's electrical. :)

Richard
Click to expand...
What's 2T mixture? Thanks
 
Rum Run said:
Hello all, I have a question regarding a Mercury 2.2hp two-stroke outboard which will not start.
The spark is good, fuel is flowing ok and the carburettor is clean. However it refuses to start, just occasionally kicking back and trying to pull the pull start handle out of my hand.
Looking at the points the gap measures right, but when probing through the spark plug hole it seems like the points start to open just after bottom dead centre which is not what I expected at all! So far as I know the points gap is the only timing adjustment-is that right? If so, what am I missing .......

Thanks in advance
Brian
Click to expand...

No I d expect the points to just "break" a few degrees before TDC, but I dont off hand know the exact figure. (5 degrees , or something like that probably)

Are you sure the gap is correct ... the specified gap should be set when the points are at their widest open point.

If the timing is that far adrift it is possible that the flywheel has sheared its key and moved on the crankshaft taper. This can happen if the retaining nut is not tightened to the correct torque.

Have you checked for a good healthy spark? It should jump at least 5mm.
 
VicS said:
No I d expect the points to just "break" a few degrees before TDC, but I dont off hand know the exact figure. (5 degrees , or something like that probably)

Are you sure the gap is correct ... the specified gap should be set when the points are at their widest open point.

If the timing is that far adrift it is possible that the flywheel has sheared its key and moved on the crankshaft taper. This can happen if the retaining nut is not tightened to the correct torque.

Have you checked for a good healthy spark? It should jump at least 5mm.
Click to expand...

Thank you VicS, the flywheel has shifted on the crankshaft and mangled the key.
I can't see how it moved though, as it took an impact gun and a mackled copy of the proper flywheel holding tool to get the nut undone.
Just waiting for a new woodruff key to reassemble and try again.:)

Cheers
 
Last edited:
Rum Run said:
Thank you VicS, the flywheel has shifted on the crankshaft. I can't see how though, it took an impact gun and a mackled copy of the proper flywheel holding tool to get the nut undone.
Just waiting for a new woodruff key to reassemble and try again.

Cheers
Click to expand...

Clean off any burs from around the keyways tighten the nut to the specified torque* so that the drive is transmitted via the taper, not by the key

* 41 Nm or 30 ft.lbs
 
Well I replaced the woodruff key and it now starts, and runs for a short while.
There is steam / smoke coming out of the piddle hole so I took the head off. There is some evidence of blowing by the gasket, and I'm fairly sure that I have had the head off years ago but didn't replace the gasket at that point. Should I replace as a matter of course or will reassembling with RTV or similar do?
Additionally, the head bolts were pretty corroded, is there a magic goop to slap on the new ones and would replacement with A4 stainless be a good move?
Thanks in advance (again)
 
Rum Run said:
Well I replaced the woodruff key and it now starts, and runs for a short while.
There is steam / smoke coming out of the piddle hole so I took the head off. There is some evidence of blowing by the gasket, and I'm fairly sure that I have had the head off years ago but didn't replace the gasket at that point. Should I replace as a matter of course or will reassembling with RTV or similar do?
Additionally, the head bolts were pretty corroded, is there a magic goop to slap on the new ones and would replacement with A4 stainless be a good move?
Thanks in advance (again)
Click to expand...

Hi . I woukd replace the head bolts....stainless or mild steel. Definately replace the head gasket and possibly impeller
 
Rum Run said:
Hello all, I have a question regarding a Mercury 2.2hp two-stroke outboard which will not start.
The spark is good, fuel is flowing ok and the carburettor is clean. However it refuses to start, just occasionally kicking back and trying to pull the pull start handle out of my hand.
Looking at the points the gap measures right, but when probing through the spark plug hole it seems like the points start to open just after bottom dead centre which is not what I expected at all! So far as I know the points gap is the only timing adjustment-is that right? If so, what am I missing .......

Thanks in advance
Brian
PS the last ditch backup Seagull Featherweight which hasn't been used for two years and has three year old fuel in it started second pull.
Click to expand...

My Mariner (same as Mercury?) manual says there is no timing adjustment. It also lists two types of ignition system, one of which, it says, results in the plug firing on both the top and bottom stroke.

Www.solocoastalsailing.co.uk
 
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