HELP PLEASE!

[geauxsaints337]

I have a 25 hp Mercury Mariner Japanese Commercial tiller handle motor. The guy I bought it from said the dealership told him is was between a 1981 and a 1985 year model.

I've never really had any trouble starting it until I left to go on vacation and when I came back, it will not start. It started one time when I choked it then after that it died and I've been pulling for at least an hour an a half with nothing. I know absolutely nothing about motors so any help would be appreciated. Thanks in advance!

 

[gm280]

:welcome: geauxsaints337 to iboats. Nice to have you join us...

So you have an engine the won't start anymore. Okay, in order for any engine to run, it needs fuel, air, spark, compression and timing. If any of those are missing, it will never start and run. So what you have to do is figure out which one or more of those things is missing. Spark is one of the easiest to determine. Remove the plug wire and buy a spark tester (about $4 dollars at any auto parts store) and us it to see if you have spark to each cylinder. It should spark at the 7/16" setting with a blue color spark. If not, then you have already figured out what is missing. If it does, then we need to move on to the next test. Mix up a little squirt bottle of 50:1 fuel oil mixture and spray in a little into the carburetor opening. See if the engine will fire and run or even try to fire. That would mean you don't have fuel going to the carb to support the engine running. If that is the case, then you have either a fuel pump issue or the carb itself needs rebuilt. I would bet that between those two separate tests you will find your problem. The timing and compression can be a problem, but unless you have a totally worn out engine, there should be enough compression to at least try to fire. And if the timing was out, you would have had problems and it would have not fired even once with the choke closed... Do those tests and post back here what you have discovered... JMHO!

 

[geauxsaints337]

Thanks for the warm welcome! I may have done these tests in the wrong order while waiting on a reply. I sprayed the mixture into the carb and on the second pull, it started for a split second then died.

I messaged the guy that I bought it from and he said to pull out the spark plugs and crank a few times to dry out the cylinder. While doing so, I noticed only one of my spark plugs is sparking. So I moved the non-sparking plug to that wire and it sparked as well. In the meantime, the other one is still not sparking. Does this mean I have a bad spark plug wire? If so, how hard is to change?

 

[cwlson]

Sounds like you need to pull and clean the carb. If you sprayed fuel into the carb and the motor fired it sounds to me that your not getting fuel. Try an empty water bottle with fuel in it with a tiny hole in the cap squirt a little fuel in the carb and start the motor once it fires see if it will stay running. If you mist fuel into the carb if it runs you definitely need to clean the carb

 

[geauxsaints337]

I've already tried that and it died out after a half second.