Odd question about my Merc.

[hdodt]

I have a 1972 Mercury 9.8 HP Model 110. Having trouble getting it running. It will run when its out of the tank no water going through it, but when I start it in the tank, it will start then die and not fire anymore. Is there anyway that the water would affect it? Thanks,

D

 

[ss von scalliwag]

Re: Odd question about my Merc.

The water shouldn't really effect the running of the engine appart from an increase in exaust back pressure.
HOWEVER,
If you have run the outboard WITHOUT water chances are you have done some damage to the impeller, waterpump and possibly overheated the engine (depending on how long you run it without water) causing severe internal problems and thus losing compression.

Just some advice for the future : YOU SHOULD NEVER RUN AN OUTBOARD ENGINE OUT OF WATER. EVER.

 

[hdodt]

Re: Odd question about my Merc.

The water shouldn't really effect the running of the engine appart from an increase in exaust back pressure.
HOWEVER,
If you have run the outboard WITHOUT water chances are you have done some damage to the impeller, waterpump and possibly overheated the engine (depending on how long you run it without water) causing severe internal problems and thus losing compression.

Just some advice for the future : YOU SHOULD NEVER RUN AN OUTBOARD ENGINE OUT OF WATER. EVER.

I understand that it shoudnt be ran out of water, and I understand what could happen to it if it is. The lower unit is off the leg to prevent impeller damage. It is never ran for more than a few seconds. When I start it out of the tank it runs great. I put it in the tank and it will start to pump water and then dies shortly after. I found a bad ignition coil, gonna swap that and see. I just posted this question wondering if there maybe was a seal or gasket that would allow water to get into the engine somewhere and make it run bad. Thanks,

D

 

[w2much]

Re: Odd question about my Merc.

I believe there is an exhaust plate on the side. Had one on my mariner. If the gasket is bad you will have the issue you speak of.