50HP Mercury Getting Too Much Gas

[sfryz]

I have been trying to get my '66/67 Kiekhaefer Mercury to idle properly. I was told to decarb my engine, which I did, and that did not help with my idling issue.<br /><br />As I was watching the engine run I noticed that there was fuel coming from both carbs near the floats. After inspection I noticed that there's a hole to let excess fuel escape.<br /><br />Is this supposed to do this all the time? It seems like the engine is getting way too much gas. When the engine seems like it's flooding I'll disconnect the fuel line and the RPM's come right up until it's out of gas and dies. <br /><br />Could the needles be sticking for the floats? Also, I noticed that when I was decarbing the engine that it would only cough when I sprayed the decarb in the top carb. The engine had no reaction when I sprayed it in the bottom carb.

 

[RICKRICK1]

Re: 50HP Mercury Getting Too Much Gas

sfryz,<br /> <br />Sounds like you need to rebuild you carbs, had same problem on 67 65hp merc. Be sure and get new carb float seats. Some of the carbs have a small plastic/rubber valve seat in them and it will need to be replaced, carb kits and seats about 16.00 each.

 

[sfryz]

Re: 50HP Mercury Getting Too Much Gas

Thanks RickRick1,<br /><br />I ordered the carb kits today ($60/carb). There's only one marina in town that can get the parts for me so I'm S.O.L. for saving some cash. Hope this works!<br /><br />sfryz

 

[RICKRICK1]

Re: 50HP Mercury Getting Too Much Gas

sfryz,<br /><br /> Kits (gaskets) run about $13 and new float seats about $9 here. Your carb sets may have new neddles and jets, thus the added cost. Blow air or carb cleaner through all the passages and then soak the parts in carb cleaner over night. My old float seats had a rubber seat. Besure you get all the old parts that you are replacing out. I used the proper thickness drill bits to make my measurements (easier than a ruler). Good luck and you will notice a difference on first trip out. The settings for throttle stop and idle will need to be adjusted, DONOT adjust spark advance at all.<br />Hope this is helpful.

 

[sfryz]

Re: 50HP Mercury Getting Too Much Gas

RickRick1,<br /><br />Thanks for your help. I actually broke down both carbs yesterday and found that the needles were sticking really bad. After I cleaned them out I had no problems with gas pouring out of the carb.<br /><br />I did notice one funny thing though. (I'm new to boating so this may have been the case the whole time and I just didn't know) My bottom carb seems to be for idling and low end performance and my upper carb seems to be for fast idle and top end.<br /><br />How did I notice this??? Well, the engine would run fine with the warm start lever pulled all the way forward. No matter how I adjusted the bottom carb the engine would run fine. As I would pull the lever back the engine would run rough. I tried adjusting the top carb and I could turn it all the way in and nothing would happen. I then started messing with the bottom carb and the rpm's came right up! I set the lower carb where it ran smoothest, pulled the warm start lever down and it purrs like a kitten! I think the thing is ready to go. I'm cancelling my carb rebuild kits today and saving $120!!<br /><br />Do the intakes on these engines work like a 4 barrel on a car? I wouldn't think that they would, but mine seems to. Any thoughts???

 

[RICKRICK1]

Re: 50HP Mercury Getting Too Much Gas

sfryz,<br /><br />Sounds like you got it possibbly fixed. Get some marine carb cleaner that you add to your fuel tank. You may still need to rebuid you carbs. Also adjust both carb needle valves to the same about 1 3/4 turns out, run it on the lake to test, if this does not seem like it helps adjust them to 2 turn out. I'm not sure but you may have one carb running leaner than the other which will drastically shorten the life of your motor. The idle speed will change if it was not adjusted in a test tank(barrel) than what it was on the muffs. Also if carb set to lean you will stall when you shift into gear. Happy boating. Mine is a 67 56hp on a 1984 15 ft tidecraft. I get 30-32 on speedo and am happy.

 

[sfryz]

Re: 50HP Mercury Getting Too Much Gas

RickRick1,<br /><br />I was running the motor in a test tank and I did put it in gear at idle without the motor stalling. I ran it up (in gear) to full throttle and back down without any problems from the motor.<br /><br />I'll have to check how many turns each carb is out. I know that the top carb is less than 1 and I think the bottom is more than one. (What could happen if they are drastically different?)<br /><br />I'm taking her out on Sunday to see how she'll do.<br />Thanks again for your advise.<br /><br />Steve

 

[RICKRICK1]

Re: 50HP Mercury Getting Too Much Gas

sfryz,<br /> The top carb sounds like it is too lean. this can cause bearing failure and damage to the cylinders. I usally start both carbs at 1 1/2 turns and adjust out from there. Anything below this is lean and you will probably get poor performance at idle when shifting and on takeoff. I know there is someone esle on this post who has had the problems with a lean carb, jump in and give us your ideas.

 

[RICKRICK1]

Re: 50HP Mercury Getting Too Much Gas

sfryz,<br /> How did it go Sunday? How did the motor do at those carb settings?

 

[sfryz]

Re: 50HP Mercury Getting Too Much Gas

We got rained out on Sunday! So she's leaving tomorrow to go out on the big lake this weekend. We'll see what happens. <br /><br />I did do some more research and found that the carbs do have to have the same settings. They are now both 1-3/4 turns out.<br /><br />We'll see what happens this weekend. Thanks for asking. I'll give you an update on Monday.