Hard starting (when cold) 1993 mercury 15hp

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Paul W

Well-known member
I have this motor on my (bluebill) duck boat - it has been getting harder and harder to start the first time for the morning hunt the colder (32 deg here today) it gets. It takes many (like 20 the other day, like 40 today) the more times i pull the recoil, eventually it does start, but it runs half a second or less, then dies - and eventually (i mean eventually) it starts and runs. there are no fuel leaks I can see inside the hood, the bulb stays firm - I'm at a total loss.

I replaced the plugs with the factory NGK BP8HS-15 - even though the old plugs were mint - both cocoa brown, electrodes looked great.


I am not sure where to go from here,? Anyone own a same design motor that can help?

After running for a while it starts on the first pull. During the summer it always started "cold" after 4-5 pulls and fired and ran, just figured it would do that no matter the temp.

Thanks in advance, guys. I have REALLY enjoyed hunting in the bluebill.

Paul
 
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The "primer" systems on mercs are annoying (sometimes a normal choke and throttle would make life easier) but havin the shift in the handle is awesome the auto rachet strim is sweet too. I would start with a carb rebuild kit.
 
I have a 1998 8hp merc and a 2001 15 hp merc. Both have same carb adjustment procedures and both have to be right on the money for easy starting if everything else is right. If not right can do just what your experiencing. Might try that if all other things are as they should be. Also runninmg some seafoam thru a tankfull of good gas will help with any deposit issue if carb hasn,t become completely fowled.
 
If it's like my '99 25HP, as Mr Finch points out, there's a primer system that can get hung up. If you follow your choke linkage, you will see where part of the linkage tries to depress a blue button, that is the priming system. It may take a squirt of PB blaster or Liquid Wrench to free it up and lubricate it. You pull out the choke knob, and pull a bit more and the knob will move another 1/4", to prime the motor. 2-3 times is good. I'll try to follow up with a pic in the daylight. I had the same problem until I think Huntin' Dave came to the rescue and explained the above to me, after I had the motor 3 years.....

Jim
 
Paul,
I had an old early 1980's 9.8 merc and ~1988 28 HP envinrude around 2004. Both where a little finicky to start. Cleaned the carbs by disassembling and soaking in the old gallon sized "parts cleaner" they sell at auto stores, and both started easy and ran like new after that. Not sure if the EPA has made them tone down the formulation of that stuff, but those cleaned carbs sure made a difference for me.

-Bill
 
Here is the button with the choke knob fully IN



Here is the button with the choke knob OUT.....but it goes another 1/4 inch or so out to depress the blue button. Try reaching in with your finger and depress the button a few times to see if it frees up.


 
The "primer" systems on mercs are annoying (sometimes a normal choke and throttle would make life easier) but havin the shift in the handle is awesome the auto rachet strim is sweet too. I would start with a carb rebuild kit.
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Thanks for the advice!
 
I have a 1998 8hp merc and a 2001 15 hp merc. Both have same carb adjustment procedures and both have to be right on the money for easy starting if everything else is right. If not right can do just what your experiencing. Might try that if all other things are as they should be. Also runninmg some seafoam thru a tankfull of good gas will help with any deposit issue if carb hasn,t become completely fowled.
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Well, it runs excellent once started, I dont think there's any issues there. I usually run a little seafoam in evey tank of my small engines.
 
I had a hell of a time starting my 25 hp Merc until I figured out I wasn't priming it. Mine has the choke/idle adjustment knob on it. Have to pull it all the way out 3-4 times to prime. Once I do that, she starts on the 1st or 2nd pull.
 
 
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Yep, that was the same thing I was doing. Frustrating as hell, one of those DUHHHH moments in the life of a boat owner!!!!!
 
Thats actually the problem previous owner had w/ my 15. Wasn,t getting it choked/ primed right and couln,t get it to stay started. Helped a lot w/ the purchase price when I offered to buy it from him. Had set up for 2 seasons when I got it. Cleaned and adjusted car. and it starts 2nd or 3rd pull when cold. First bump when warm!
 
I suppose now would be a perfect time to make a smarta** remark about Mercs but then I may need a tow from that very motor if my neglected OMC should fail on me Tues., right ol buddy ol pal??. Karma is not to be neglected.
 
O dark thirty not a good time to find out you,ve got motor issues!... Been there, done that, fortunately not in a long long time. Always pays to have either a duck boat fleet or a good bac-up plan. Duck boat fleet is more fun!
 
I suppose now would be a perfect time to make a smarta** remark about Mercs but then I may need a tow from that very motor if my neglected OMC should fail on me Tues., right ol buddy ol pal??. Karma is not to be neglected.
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this thing runs like a top, now that the "user error" has been taken out of the equation, it starts immediately every time! I walked by it and started it a few times today just for FUN!
 
Tom,

There is a reason all mechanics like OMC products,,,,,,,,,,,,,,,,,,,,,,,,, Those mechanics have made a fortune working on them!!

Mercs on the other hand never need a mechanic. (smirk, smirk,)

Ya I know, now I'll be the one needing a tow. Maybe karma will miss me as I am running a Yamaha now. :>) :>)
 
Actually primed the motor this morning, 28 degrees, and it fired and ran on the first half pull.

I like this motor much more now! Haha! Thanks guys !
 
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