1980 Mariner 30HP possible exhaust problem

[dcm3372]

Hi,

My Mariner recently developed a strange problem.

It started and ran perfectly as usual, but it suddenly started running rough, wouldn't idle and stopped pumping water.

At full throttle it seemed to run fine (I only tried this briefly). Back at the yard in my test tank it was the same. The water pump looks fine and had an impeller recently and yet no water from the tell-tale.

I get 125 on both cylinders with a compression test which makes me think the head gasket is fine.

I wonder if it might be one of the gaskets between the exhaust and the water jacket? I imagine it might effect the water pumping, but would that account for rough running?

Prior to this the engine was sweet.

 

[tashasdaddy]

Re: 1980 Mariner 30HP possible exhaust problem

first with no telltale, you have no cooling, the tt is the last thing in line, the block fills and then the pressure of the impeller pumps water out the tt. if it is pumping the water is not getting there, an exhaust leak in to the cooling system, stops the flow of water. or a pressure leak in the head does the same thing. they push the water back down the tube. good call. check it out.

 

[fixerupper]

Re: 1980 Mariner 30HP possible exhaust problem

I have a 30E mariner that I replaced the drive shaft and pinion gear along with an water impeller and gasket kit. Everything was running great until the other day when it started running rough and a popping noise came from the exhaust in the lower unit.(almost sounded like it was back firing) At home in test tank the stream of water stopped flowing and the popping seemed to be coming through the propeller. I got the lower unit off and everything looks good, I'm lost could this be a gasket like the other gentlemen with the possible exhaust problems? The parts and the repair manual I purchased from iboats helped me so far. I know where to get good deals for my parts but now I don't know what else to do just yet.