60 hp 3 cylinder 2 carbs HELP

This early 70's Mercury motor has good compression 150, 145 and 145 also has good spark to all 3 cylinders. will run and idle but is not running on the middle cylinder. I pull the middle plug wire and it has no effect. Pull either of the others or both at the same time it will die. I think it must be the reeds that feed the middle cylinder are stuck shut. I cannot even see them. I think that the only way to get to them is to split the cases. Could those reeds be stuck? Does the engine need to be "loaded" to pull fuel through the reeds the the middle cylinder? any ideas will be appriciated.

The reeds are accessed by removing the carbs then the induction manifold/plate.
Shouldn't need to split the block.
Have a look here, pick your ser#
https://www.mercruiserparts.com/selectSerailRange.asp?doc_nbr=60+%283+CYL.%29

I looked my ser. is OB357xxx and the reed blocks are bolted to the crank shaft and double as main bearings. Positioned behind each carb fuel/air from the carb into the reed block and is pulled up to the top cyl.through the reed valves or down through the bottom reed valves to the middle cyl. as demanded. The middle cyl also pulls fuel/air up through the bottom reed block. Maybe i'm not seeing it but it still looks like to get to the reed blocks you must expose the crank

Ok if you looked it up I'm sure you are correct. I was just looking at a similiar motor (not exactly your configuration).

If that center cylinder is getting lots of spark--and the plug does not shown any sign of water on it--then it MIGHT be reeds, but I doubt it. If they were that bad the adjourning cylinders would run awful and it would shoot gas out the front of the carb.

Jeff

PS: Hate to say it, but I've seen one of those motors that, tough had 140 pounds compression, it also had a cracked block and wouldn't run on that cylinder.

Found it(bad news)I'm getting water in the middle cylinder. Must have that cracked block. It must be below the piston and transfering to the top side through the transfer ports, due to the fact that it does have 140 lbs compression.

Don't rule out that it may just be a gasket leak inside the exhaust manifold!
There are 3 gaskets (I believe) in that area.

Without looking at your engine, you may be able to remove the transfer cover (on the side of cylinder block)
Manually turn the flywheel until the middle piston uncovers the cylinder
Hook up your flushing rig and turn on the water, and you may be able to see across the cylinder for a water leak..
Try looking thru all the cylinders if you don't see it from the middle one.

Not sure if it's possible I'm just thinking out loud here cos I'm not looking at an engine.

Thanks "trynhooker" and "fastjeff" I am trying to figure out if a gasket on the exhaust side would cause the loss of vacumm that I have going on. I am going to check this out tonight. Maybe I can see into the cylinder from there.