Hard starting Merc Solution

Carl

Carl

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My "new" Merc 2-stroke has always been hard to start the first time. Once I get it cranked once, the rest of the day it fires up with 1/2 pull. But the first time, I had to pull that damn thing 20-30 times to get her to crank. Really made me miss electric start on my old Nissan.
So I did a little internet searching and immediately found a good thread on a small outboard site.
Thought I would share what I found out for all you Merc Owners:
The primer/idle adjuctment knob pushes down on a little primer pump on the side of the carb when you pull it out. Basically, it shoots a squirt of fuel into the carb. Apparently, either the knob tends to hang up a little or the blue button on top of the primer pump can tend to hang up. So when you pull out the knob, it may feel like you are priming it, but you are not.
Solution is to pull the cowl off and observe the primer pump on the side of the carb as you pull the knob. If it is not being fully depressed, gently push it down (you should hear a squirt) and then try the knob again a couple of times. Once I worked mine like this a couple of times, it worked great and motor cranks up on the first pull now after just two pull on the primer. Even if your primer/idle adj. knob breaks, you can still pull the cowl off and push the blue button on top of the primer pump to prime the motor.
Hope this is helpful!
 
Carl, Good catch!! It just goes to show the best policy is to "know your enemy" A lot of guys out there could stand to get more farmiliar with there outboards.
 
Carl, I bought a 25 merc back in the mid ninetys, it was what they called a program motor. These were motors mercury leased to resorts for a season, then take back in the fall, give them new motors again in spring. My motor was lightly used and as close to new as you could get. Only hitch was, like your motor it was really cold hearted in the mornings, then good to go for the rest of the day. I took it to a local shop after a few years and had him look it over, change lower unit lube, compression test etc. Told him about hard starting. A couple days later the mechanic called and said I could pick it up as he was finished with it. When I was picking it up I asked him about the starting problem. Mechanic said it started first pull every time.I asked him what he did, he said nothing. I said show me! we took it off my truck, put it on a stand, slid the muffs on the lower unit. He then proceeded to pull the choke out TWO NOTCHES! and it started on first pull. No one ever showed me that second notch on the choke pull knob,all I was ever doing was setting it on fast idle. What a dummy! Well that was ten or more years ago. Still runs and starts like a new motor, even in 20 degree North Dakota mornings.I just never read the book. Dont laugh too hard. Rich
 
Primer/Idle Adj. Knob on front of motor (pulled 1/2 way out). Small Mercs dont have a traditional choke , you pull this out all the way to prime the carb to cold start. You also turn this knob to adjust idle speed.

View attachment Primer_Idle_Knob1.jpg

Primer Pump Button, under cowl, onthe right side of carb as you face the stern. This can tend to stick, simply press down gently to free up. Whiles its pressed, work the Primer Knob in & out to make sure it is not hung up as well. That little black plastic arm above it is what pushes down on the button when you fully pull out the primer knob.

[inline PrimerButton.jpg ]

Primer Pump Button depressed, it pops back up automatically (or should anyway). As it depresses, you will hear a squiirt of fuel going into the carb.

[inline PrimerButtonDown.jpg ]

View attachment PrimerButton.jpg
View attachment PrimerButtonDown.jpg
 
I'm not laughing, I was doing the same damn thing!!!
At least I managed to find a solution before duck season.
 
Carl,

Are you using the blue sta-bil every time you get gas. If you aren't I would start. It should help and can't hurt. 2-strokes gum up within 2 weeks. Thank you ethanol. I'll be down there in a few weeks.

Ben
 
Carl,
I own two of those. A merc like yours and and Mariner that is the same motor only the thing was tweaked for the commercial market. The Mariner carb has no knob just a pull choke that closes the butterfly. No carb squirt pump. If that motor dosnt start on the second or third pull something is wrong.
Great pictures and tip on the Merc setup.
They are very good motors and make good power for the weight.

Bob
 
This problem sounds like my 1999 2 stroke Mariner 25hp....will check mine out tonight.....

The other thing that I didn't realize is that turning that "choke looking knob" adjusts the idle....
 
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I use Stabil for Ethanol and Sea Foam in every tank.
It starts fine when the primer is correctly operated!
 
HA! How about that....I got home before dark and popped the cover on my Mariner...... Blue button to the right of the carb!!! Pressed it and it seemed stuck. Didn't take a lot of pressure to feel it "pop", then it moved freely. Heard the sound of fuel being injected (probably just air because I didn't squeeze the bulb first).... I expect a better initial startup tomorrow morning

THANK YOU FOR THE TIP!!!

Jim
 
Rich and anyone else tempted to use ether on a gasoline engine - DON'T DO IT!!!!!!!!!!!!!!!!!!!!!!!! That stuff is for diesels and can literally blow an engine up. At the Tecumseh factory school that I attended in a former life (1979) they had a display of a snowblower engine that was now a cut away, split right down the side. Even if it doesn't blow up it will dry the cylinder walls of any lube and make it hard to turn and have metal to metal when it starts. Best kept secret--- Use WD-40 instead. Good luck
 
Tom, when I was a kid almost all diesels were started with either in cold weather. they were low compression non turbocharged engines. Many of them had a zillion hours on them. Modern high compression diesels will do exactly what you describe if you use either in them. I am not a chemist but I think the modern starting fluid they sell in auto parts stores is not nearly as volitile as the old medical grade either used 50 or 60 years ago. If it was that dangerous I cant imagine BIG BROTHER would allow it to be sold to the public. I have been using it occasionally for years without a problem. I can imagine some inexperienced person could load so much into an engine as to blow it apart. In fact if it wasnt for that starting fluid I probably would have unclamped that motor and dumped it in the creek! Rich
 
I'll share mine.
I had a mid 80's Merc 150 that would start fine every time. After about a half hour the engine would die. I could be blasting accross the water full speed or trolling and it would just die. After about a half hour it would start up again as usual and a half hour of run time, die again. I had a repair shop go through it, say they fixed it and then it would happen again. I told them I thought it was in the wiring because it just cuts right out like a light switch, they say no because if it was then why does it start back up later. Ok, what do I know, they're the experts and I continued to have it in and out of the shop for most of a summer. Eventually and FINALLY, the mechanic said he would go for a ride with me, I told him to bring his tan lotion since we'd be out here a while. We jump in the boat and of we go and just like clock work it dies, then starts, then dies. He'd take the cowl off it, tinker each time it died with no luck... it only started a half hour later. We finally get it back to the dock and he says it seems to be starting only after it has a chance to cool down. Then he looks at me and says he thinks it electrical, hmmmm. He then proceeds to remove what he called the black box or brain, which if I remember correctely was basically a bunch of electrical connections encapsulated in plastic. From the front the box looked fine, when he took it off and looked at the back side, which was also the side nearest to the power head, you could see a hairline crack. So basically what was happening was when the engine was cold or cooled down the wire ends would touch and make their connection, when the engine got hot the crack would expand and break the connection. And thus the cycle repeated itself. it was nothing you could see from the front. It was a very time consuming lesson for me that hopefully helps someone here.

Mark

Oh and Carl, I had a 1989 18hp Merc that did the same thing yours did every time in all weather. I took it in and had it gone through by a different Merc mechanic a couple different times with no luck. Not wanting to get stranded on open water in a Michigan November I sold it to a guy that liked to tinker with outboards... he probally found the issue as soon as he got home. I loved the forward and reverse on the handle and wish I had known then what you just shared.
 
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