Mercruiser 140 3.0 gets fuel and spark but still won’t fire up

[Guywiththev-164]

Ok guys I need serious help I have a mercruiser 140 3.0, everything started about a year ago, I took the boat out one day it ran fine, I tried to take it out the next week and it fired up but as soon as I tried to give it gas it dies so I took it back home thinking it was the idle/air mixture screws and I re adjusted them and it struggled but it fired up one time it ran for about 10 seconds and it died so I set it aside for about a year and I just bought a brand new carb that has been bench tested and it was basically a plug and play part so I put it on and went to fire it up and I got no spark so I thought it was the coil and I replaced it and I still got nothing so I cleaned the point in the distributer cap and I received spark but it seems weak usually blue or white spark is seen but this spark is orange but i don’t know that there’s a big difference because a lot of people say a spark is a spark but anyway I’m getting spark now and I know I’m getting fuel, I did not replace the distributer cap the condenser or the points on the ignition system. When I try to fire it up it turns over and then stops mid turn like it gets hung up and I smell the gas being burned so it leads me to believe it’s the distributer cap because I had a 2005 gmc truck that had a v6 and it had and ignition with the distributer cap and it did the same thing and I was stuck on it for weeks, the truck turned over and stopped like something was hanging it up I don’t remember if I was getting spark out of the truck but it sounded like it wanted to fire up so I turned to the internet and found something similar and the guy replaced the distributer cap and it fired up so I did that same thing and my truck fired up so I’m not sure where to go from here much help needed thanks in advance

 

[kenny nunez]

Go to a NAPA store and get the points and condenser that will give you a much better spark. Their stuff is much better than the junk from the “Big Box” auto stores. If they ask you what vehicle the points are for just say 1970 Chevy truck 6 cylinder. Also buy a new set of spark plugs as these are fouled. The best thing would be for you to convert over to a Petronics electronic ignition which is highly recommended by everyone on this site.

 

[Guywiththev-164]

So you also believe my problem has something to do with the distributer

 

[Fishermark]

Not the distributor specifically, but yes, the points and condenser. The "stopping in the middle of cranking" simply indicates a weak battery. Put your battery on a charge and get some new points and condenser and see if that helps.

 

[Fishermark]

By the way - take a little time to do some reading in the "adults only" section at the top of the page. (It's not what you think it is!) There is a lot of good basic info on this that you need to know.

 

[Bondo]

By the way - take a little time to do some reading in the "adults only" section at the top of the page. (It's not what you think it is!) There is a lot of good basic info on this that you need to know.

Ayuh,..... Welcome Aboard,....... Or click on the link in my signature that Mark speaks of,......

 

[Guywiththev-164]

I just bought a new battery as well so I don’t think it’s the battery, I happened to read somewhere that it could be the positive lead or my starter is bad. When I’m turning it over It will stop mid turn sometimes and when it does that I get discharge from the carburetor. The positive lead gets hot and I see smoke coming from the distributer area so I’m wondering if it could be that my condenser is not working properly and getting the point hot to where it starts smoking

 

[Fishermark]

The fact that your positive lead gets hot is an indication of either a loose/corroded connection which generates heat... or excessive draw of current. It could be your starter is binding or the the engine is tight. Start with the easy thing and make sure your connections are clean, shiny, and tight. If you have wing nuts, throw them away and use a regular nut that you can tighten down with a wrench. Better yet, use regular automotive style battery top post battery terminals instead of the ring terminals on the battery.

 

[Guywiththev-164]

I’m going to go over what I’ve done and what Ive seen the past few days. I first had a no spark situation I since then have replaced the coil, distributer cap and rotor, points and condenser, and the spark plug wires I now get a good blue spark coming from the spark tester I’m unsure about the plugs themselves but I changed them over to my old ones and I still got the same results, every other time I try to start it, it back fires out of the carb and if I open up the throttle just a little bit I get more reactions out of it or if I have one of the spark plug wires off the plug it seems more like it wants to fire up, I’ve replaced all ignition components except the spark plugs themselves. The battery is new but the starter does turn the motor over a bit slow, the carb is refurbished, it looks and operates like new. I don’t get it I have fuel and I have spark it should start up. The carb was pre set before it was sent to me it was essentially a plug and play carb I’m just curious that if the idle/air mixtures are not right that I wouldn’t at least try to almost start or start and die right away, I feel like it’s getting way too much gas because I can smell it being burned, the carb back fires and when I pull the plugs they are wet I’m not sure what to do from here so any ideas would be greatly appreciated I really wanna get this thing on the water also I was wondering if the shift interrupter switch would let it have spark but not crank up