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Mercury 50 hp, 4 cyl, 1984 Model el

D

davio47

Member
Just bought this outfit a few weeks ago. Ran beautiful in the driveway, click started every time I tried it. Took it to the river today and it would just crank and would not start. Drove it home and tried it again and it started right up. It then would not start but crank. The stator was replaced last year . After starting it in the driveway, turning it off and on. It progressed to where it would not start again and just crank. I noticed gas dripping out of the top carb. Is this a fuel flooding problem? Any suggestions out there? I would love to hear from you.
Happy Easter,

Dave:(:confused:
 
Compression/spark.Then start with fuel pump/rebuild.Replace all the hoses ,and inline connectors/remove.Clean the carbs.Check for water in the gas.
Ethanol is a problem.J
 
Worked on it tonight for a bit. I got new fuel lines and fuel filter to start with. Also I just got a new tank with fresh fuel. Compression and spark will be looked at tomorrow. I will keep you all updated on my progress. Thanks for your input so far. Much appreciated.

Dave
 
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Spark and compression are good. With new fuel lines and clean fuel I put the battery back on and tried to fire it up. She fired and didn't want to keep running. I shut it down and pumped the ball. At this time I notice the fuel was leaking out of the fuel pump on the upper carb. Carberator rebuild and adjustment is next. Will keep you all updated on my progress. Any suggestions out there on my repair strategy will be appreciated. Thanks.

Dave
 
Hey mate. I have the same engine and am working on a rebuild at the moment.
Like the others said, check your spark and compression. Make sure all cylinders have roughly the same compression, 125psi is ideal.
Pull out the spark plugs and let them hang with the leads still on the plugs and crank her and watch for the spark (or listen out for the clicking of the spark). I have read that its not good to test it this way, but its worked fine for me with no issues many times.
Also, check the plugs to see if they are fouled. Are they oily and black? or dry??

Finally, the fuel coming out of the carby is normal. When you pump the bulb it will overflow. When using the choke it does the same. Nothing to worry about there. When cold cranking it pumps a crapload of fuel in to the cylinders to get it going. (At least I believe its normal because mine does this when I start her up with choke or when I prime her before starting, and the engine would run like a dream after a carby recon)

So basically, you need to check your spark, compression and fuel. Finaly thing on the fuel to check is to make sure it is being pumped in to the cylinder. When was the last time you did a carby clean our/recon? How is the diaphram pump? In good condition?
 
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One more thing. When starting the engine (cold) use the choke and give it full throttle (using the 'throttle only' button on the throttle lever). Once the engine starts remove choke and reduce throttle until it runs smooth. Make sure you check your fuel tank to engine for air/fuel leaks and open the breather on the petrol tank to avoid a vacuum in the tank.
 
Thanks for the great advice and insight into the idiosyncratic nature of the motor. I am having the carbs rebuilt. I will keep the thread going after I get it that done and let you know my progress. Thanks.

Dave
 
..."When starting the engine (cold) use the choke and give it full throttle (using the 'throttle only' button on the throttle lever). "

This needs more definition or it might cause somebody SERIOUS trouble! What he is referring to is the idle up control tharaiseses the idle speed to max for starting. It does NOT open the throttle wide open. That particular old Merc likes a bunch of throttle to get started, but not WOT!

Jeff
 
fastjeff said:
..."When starting the engine (cold) use the choke and give it full throttle (using the 'throttle only' button on the throttle lever). "

This needs more definition or it might cause somebody SERIOUS trouble! What he is referring to is the idle up control tharaiseses the idle speed to max for starting. It does NOT open the throttle wide open. That particular old Merc likes a bunch of throttle to get started, but not WOT!

Jeff
Click to expand...

Thanks for the clarification. :)
When using throttle only to start it limits the amount of throttle you can use (wont go to WOT). If you accidentally put it in gear and to WOT then the engine shouldnt even crank as you cant start it in gear.
 
Compression is 140 psi on all 4 cyl. Spark and electrical were also good. Carbs are being rebuilt now. Should run well after that. Will let you know the outcome soon.

Does anyone out there have a power trim and tilt unit that will work on this motor. Will be interested in hearing from you .
Thanks,


Dave
 
Carbs are rebuilt and installed. Cleaned tarnish from body with a good soaking, new carb kit and new floats as well. Runs like a watch. I believe the floats were sticking and of it needed the rebuild. I am going to use a fuel conditioner from now on. Later.

Dave :cool:
 
Bought this outboard from davio47 in the hopes of upgrading from the old Evinrude I have on my old Whaler. Started her up today only to find her shutting down when brought to neutral. Cranked her over again and kept her going by keeping the rpm's up. Shut her back down and attempted to restart. Only cranking. Sound familiar? I was had by a Craigslist Ad, and never told of the actual condition of this motor. It was already taken off his boat when I arrived at his house. Trusted his Youtube video. Damn. Wish I would have seen this prior to purchase. Only found it while trying to troubleshoot via Google. I wonder if davio47 was mislead by his mechanic as well.????
 
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Back the idle screws out a 1/4 turn,see if that helps.But do a compression check as well.
A leaking crank or top or bottom seal will cause the same problem.
 
From what I know from davio...compression and spark was good and all electrical components replaced. Checked spark myself and it was good. Do not have a compression check gauge, so I 'm taking his word for it. Decided since the motor wasn't running right, to take the carbs off and look at them (that's what I know). What I found was 3 missing gaskets in the fuel pumps, a mis-assembled baffle in the top carb that would not allow the float to move, and a missing venturi. Have them rebuilt after getting the parts from Mercury. Will attempt to run her tomorrow.
 
I had to do some final fitting of the fuel pump caps as gas was leaking out when I pumped the bulb. Primed the bulb and choke-started her for about 1.5 seconds. Runs like a champ, and click starts every time after that. I will try and post a video.
 
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Did notice later that day that the motor appeared to be flooded after sitting with the fuel line still attached and would not start. Unplugged it and let it sit. Restarted later with no issues. Same was true today. Ran fine, then sat, then wouldn't start, let sit, then would. Any ideas?
 
Thanks.
What's the fix?
Float adjustment is what I'm thinking??? If that's it (or not), could someone tell me what the float settings are for the Walbro carbs and how to measure them?
 
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There may be an issue with how you start the motor.-------------If you post in some detail your starting technique when motor is cold and when it has sat for a while we may be able to offer some pointers.--------Somehow I doubt that it is the float setting, since you say it runs fine once started.
 
The bulb is primed and full. Turn the key. If initially it won't start, then I turn it with the choke on until it does. Normally, she'll fire right up in less than a second with the choke on. After that, she click starts right up.

I wonder since it is a dual carb setup, that when it is off, the gas in the fuel line feeding the top carb backfills the lower carb and...that is why I feel the need for float adjustment to seat the needle valves?
 
After wearing out my fingertips on those hard to tighten/ loosen carb bolts, I've learned to "vise test" every carb I rebuild (and that's a dozen or more a month). Simply put: I gently clamp the carb in my vise, hook a gas line to it, and pump the HELL out of the bulb! (Note: You can make 15 psi with the bulb where the fuel pump makes only 4 to 6 psi.) If that sucker leaks, I lower the float a 1/16 inch at a time until is stops (or replace parts until it does). Then, and only then, do I bother to install it on the motor.

Jeff
 
Most do nowadays since ethanol gas came about--it has less energy than the good stuff. I've had to open the idle mixture screw(s) a half turn or so on dozens of old outboards that had been idling just fine before.

Jeff
 
Not really. The measurements listed in the manuals are only approximate--the parts aren't manufactured THAT accurately! Done this for years without a problem yet, BUT you don't go an 1/8 inch! Just a tiny bit--like a 1/16 of an inch--which usually fixes the problem.

Jeff
 
Thanks fastjeff, I'm rebuilding an old Merc and the factory manual says to adjust the float lever at a gauge dimension of 13/32 +/- 1/64. I though that sounded a little too tight in tolerance.
 
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