HELP..my almost new Merc 6hp 4 stroke won't start

barryg

barryg

Member
Jun 24, 2007
966
Fort Lauderdale
Boat Info
2005 320 Sundancer, Garmin 5208
Engines
Twin V-Drives 350 Mags
I've had this engine about a year for my dinghy and it has always started the first pull no problem...Now, for the last few times; it will cold start with the choke out the first tme, but after a minute or two when I get it warmed up and push the choke in it dies and won't start again no matter what. ..I've tried pretty much everything I know from changing the plug, the fuel filter, and oil, to putting some higher octane and fuel treatment in the 3gal tank; and still nothing. I let it sit; thinking maybe it's flooded, but even after a half hour won't start. The engine sits in my garage on an engine dolly when not used, so it even still looks brand new..

Any ideas, suggestions would be great as I really don't want to spend a few hundred taking this in..

Thanks!!
Barry
 
Barry,

Unfortunately, you may have to take this in. To test your flooded theory, try replacing the plug and use a little starting fluid to see if that will get it going. That will test a few things including the ignition system. If it doesn't start and run for a short period, the problem might be electrical. If it starts and dies after a short period (which is what I think it will do) then you have a fuel delivery problem.

What happens to that engine and smaller ones is the jet gets clogged and unit won't run. That requires the unit to be disassembled and cleaned. If you have the service manual it describes the process.

-John
 
John,

After giving up yesterday spending about a half hour trying to get it started, I just pulled the engine up and used the oars to paddle around the canals in my neighborhood, and also to get around my 320 so I could do a little hand compounding and polishing from the waterline up.. When I was done (as the rain started coming down again; I put the engine back down, and with the fuel hose disconnected from earlier, tried again to start (with the choke not pulled out), and wouldn't you know it started right up and .Now I'm even more confused as to what's going on, and what to do..

I don't really have a service manual for the engine, just the small merc handbook that came with it and it doesn't break things down...

Any thoughts on what I can do myself or is this something I still need to bring into an outboard mechanic to look at. I'm heading to the Bahamas in about 3 weeks and don't want to have to deal with this problem then...

Thanks
 
thanks, I read a thread that seems similar to my problem.. something about the float in the carb. Not sure if I can just spray some carb cleaner and that will do the trick, as it seems my next step is taking it to the mechanic...
 
Probably unrelated, but I had a somewhat similar problem with my 8hp. It wouldn't start, so I tried advancing the throttle a bit-with the neutral lock engaged- and it fired right up. If I twisted the throttle back to idle position, it would die.

A quick adjustment of the idle throttle set screw solved the problem.
 
You need to open the little valve on top of the gas tank because you are causing a vacuum against the fuel draw. Loosen the valve and I bet she fires up.
 
Fishnut said:
You need to open the little valve on top of the gas tank because you are causing a vacuum against the fuel draw. Loosen the valve and I bet she fires up.
Click to expand...


Exactly my thought !!!

Starts, runs, dies and hey did I remember to open the fuel tank vent....( kinda like forgetting to put the plug in )
:smt021
 
I know this sounds obvious, but it happened to me. (I felt so sheepish). Check that the hose from the tank to the motor is in the correct direction of fuel flow. Should be an arrow indicator.
 
No, The vent is open.. If anything the thing floods right away..When I take the cowling off and I pull the cord, I see gas come out of a nozzle on top of the carb. Someone said a float in the carb can be stuck or needs to be adjusted, but I don't know how to do this or why it would be what happened.
 
Barry,

You are getting plenty of good advice. The primary issue I believe is that the carb needs to be disassembled and cleaned. From time to time it may work fine. The issue is reliability. A small amount of debris can clog the jet or cause the float to stick and the result is flooding, hard starting or poor running.

-John
 
Is the bulb on the hose firm? If not try pumping it a couple of times and then starting it.

The other thing is that the breakin period for the small merc is about 25 hours of run time. I have a 8hp that drove me a little nuts until I ran it hard for a couple of weeks then it took on a life of it's own and started working like a champ.

If it is flooding, you may have something in the jet but that is a good afternoon project. I would first back off on the choke, check the fue line as I suggested and run the thing for a while if you can. In fact I would run the begeebers out of it. BTW, these motors run better the more you use them. If you aren't using it all the time make sure you have some seafoam or stabil in your gas or run the carb out when not using it. Also if you are storing it make sure you hit the carb and heads with a fogging oil. Let us know what you find out.
 
Thanks guys..

The bulb on the hose is firm, and I do put stabil in the gas; and ran the engine with the fuel line disengaged until it used up all the gas in the engine. I've never used a fogging oil as I usually put it in the water at least once a month.

Any other suggestions??? I'm hoping I don't have to pull the carb as I've never done that before and even though this is a small engine, I'd hate to mess it up more!!
 
If you are going to take it in to get looked at anyway, go ahead and take it apart. Just don't lose any parts or break anything. It will only cost a few bucks more if you take the motor in with the carb in a box, as long as all of the parts are there and not broken.

Go for it... You've got the manual... You've got these guys... You're good to go...
 
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