86 Mariner won't run right

[gprestridge]

20 Mariner runs best at high speed once cranked. Hard to crank-hits but won't keep running....keep messing with it and finally will crank usually--while trying to work on it with water muffs I noticed it was not turning over with the battery like it should-as if vapor locked..removed bottom spark pluig and it will spin freely with battery-replace bottom plug and it will not turn with battery-remove top plug won't turn.replace top plug and remove bottom plug it will turn..someone mentioned possibility of exhaust gaskets leaking. After thinking about it, does it make sense that if the exhaust gaskets are leaking, water is being forced in by them while using the water muffs? If so, am I correct that these gaskets are on the right side of the motor under the square plate and are easily changed??Thanks Akso, where can I get a schematic on this motor?

 

[gprestridge]

Re: 86 Mariner won't run right

Can anyone tell me where there is a discussion board or an individual where I might get a response???

 

[JB]

Re: 86 Mariner won't run right

Howdy, GPrestridge.<br /><br />You are already on the best forum on the internet for getting solutions to engine problems.<br /><br />If you don't get a response it is usually one of two things.<br /><br />Noone has read your post that has anything to offer, or your description of your problem is unclear and we don't know what your question is.<br /><br />Engines don't vapor lock, fuel pumps do. After rereading your post several times it appears that you may have a compression problem or you may have an electrical problem with your starter circuit. You may have both. Neither of those seem to have anything to do with your initial description of your symptoms.<br /><br />Do a compression test. Inspect your spark plugs. If you suspect water in your bottom cylinder, your plug will tell you (squeaky clean, as though never used). Clean and reconnect all high current connections in the starter circuit.<br /><br />Let us know what you have found. Please don't cram four subjects into one paragraph. That will make it a lot easier to read.

 

[gprestridge]

Re: 86 Mariner won't run right

JB, you might have missed an earlier post..One thing I said in an early post was that the bottom plug looked like new except one little spot on the firing ring.Top plug looked more like I expected it to look-slight oily film all the way around the firing ring--What if I put the normal looking top plug in the bottom cylinder and try to run it a little and see if it comes sparkly clean.If it does I'll know I have an internal steam cleaning process going on? If this happens this should mean one thing-a leaking exhaust gasket?? Is this worth trying?Also if water is getting into this cylinder this couild explain why it runs fair wide open but don't want to crank. At wide open speed it sorta overcomes the water to some degree..What do you think??

 

[JB]

Re: 86 Mariner won't run right

Hmmm. Why isn't this a continuation of the "earlier" post? What else don't you tell us in this one?<br /><br />You may have any of the problems related above, plus you may have a leaking exhaust gasket or a blown head gasket.<br /><br />Check the compression. Let us know what you find.<br /><br />Good luck.

 

[gprestridge]

Re: 86 Mariner won't run right

JB, Someone said my gauge must be wrong but-top cylinder 120# compression-bottom 140#-----someone said more like 100# is normal---could be the water in there causing a higher reading-- also keep in mind, with bottom plug installed it often does not want to crank/spin with the starter. With bottom plug removed it always spins freely-based on the super clean bottom plug and these other things-I am about ready to try replacing the exhaust gasket.Do you agree?

 

[JB]

Re: 86 Mariner won't run right

Yep. With the compression that high, it is very unlikely that you have a blown head gasket and it sure sounds like you are getting lots of water in there.<br /><br />Let us know what you find.

 

[gprestridge]

Re: 86 Mariner won't run right

Thanks-I happen to be off from work today-will let you know how I come out--thanks again...

 

[gprestridge]

Re: 86 Mariner won't run right

Places around here have crazy hours so haven't been able to ck on the part yet--am I correct in thinking this is located on the right side of the motor(facing the front of the motor)looks like remove 6 or so bolts and you can see the edge of two gaskets under these plates-is this it or is there something else behind these plates that also must be replaced--any special instructions? Should I use gasket sealer on the new gaskets??

 

[JB]

Re: 86 Mariner won't run right

You'll need to get that info from a manual, or from someone more familiar with the Mariner than I.<br /><br />Get a manual. You will need it over and over anyway. Why not get it now?<br /><br />Good luck.

 

[gprestridge]

Re: 86 Mariner won't run right

JB-this motor belongs to my Dad--actually I'm trying to help him get iy going and will strongly recommend he sell it as soon as he gets it going-he has had to replace the stator assembly last year-carb. problems over the years etc--I run an Evinrude - all you do is mix the gas-hit the starter and go---had one Mercury years ago and will never own another one....I personally won't own anything that requires a manual over and over......