120hp engine. Another year same problem.

[boater chris]

I have a 1979 mercruiser 120hp 4 cylinder gm inline engine, that will not start. engine cranks nicely but will not fire. I had the same thing happen last year during my first start of the season, we tried to troubleshoot it for two days but could not find anything wrong with the coil, distributer cap or plugs. finally after pumping a good amount of gas into carb by pushing throttle multiple times the engine mysteriously fired. It started fine the rest of the year for me in 2011. Now the same thing is happening again, this time i made sure to pump a good amount of gas in carb(I can see it squirting in) but it would not fire. I tried to sprayy some starting fluid in carb but no help. I even poured a little gas in carb but still did not even sputter. I pulled off plug from coil to distributer and can see it sparking good. i took off distributer cap and all points look good so did rotor as far as i can tell no corosion of any kind. I really am a novice only my 3rd year with a boat and im not a very good mechanic so put any response in dummy terms. THANKS.

 

[achris]

Re: 120hp engine. Another year same problem.

Replace the points. They got tarnish on them over the winter and tarnish doesn't conduct electrickery... It fired up for you last year because the tarnish rubbed through with the constant opening and closing, it won't happen this year.... Just throw new points in (and replace the condensor and rotor while you're at it), check and reset the timing and you'll be good to go. You can't see the tarnish, the points will look fine.

Chris....

 

[boater chris]

Re: 120hp engine. Another year same problem.

Okay sounds good chris. I will surely let you know the outcome after doing this. Thanks for the info.

 

[achris]

Re: 120hp engine. Another year same problem.

Remember to clean the new points before you put them in... Just with some spirit and a soft cloth...

Chris..

 

[boater chris]

Re: 120hp engine. Another year same problem.

Okay so before I went to My local Marine Shop and bought the points rotor and condenser. I wanted to take a look at the spark plugs and wires and see if I should get those too. I pulled off #1 plug and it looked good, it was not wet though it did smell of gas pretty good. while I had it off I wanted to see if I was getting spark, so I cranked the engine and grounded the plug and I was getting a good spark off of the plug. I went ahead and put the plug back in and tried to start the engine with out giving it any gas this time. It fired on the first try and now it fires everytime no questions asked. The only thing I can assume is that I had it flooded.

I am still going to change the points though because I have not done this since I have owned the boat, and I would rather not be stranded on the water.