TOPIC: Questions, help removing bottom carb on 69 #1250

Okay to follow up on my problem I posted about early this summer.
I have been experianing power stumble past couple years from idle to full throttle.

Then this year now I can idle but it dies and even when I kick up idle and it does idle, I try to put in grear and dies.

Symptons noted,
Full tilt up of motor and hard squeeze of ball shows gas coming from top 2 carbs but no gas from bottom card at all. Tried carb cleaner while running and ran on hose and in lake with seafoam but still can not get from idle to power up when putting in gear.

Guess is the jets have been getting cloged last couple years and now are clogged in bottom carb as I used to get gas leak when tilted up and primed in all 3 carbs. This one seems dry.

Things tried,
Replaced all fuel lines again and tight.
Rebuilt both fuel pumps
bolts and fittings all tight.

So I have done about all I can so I guess now its time to clean carb off the motor so I can quick soak and blow out jets.

Looking at lower carb looks pretty simple. two bolt and gas fittings a breeze. My question is the linkage removal? Does it simply just disingage and slide off the bottom of linkage in middle carb? or is there something I am missing? What is easy way?

Hope this works. Running out of ideas.

Thanks!

Let me put this as diplomatically as I can, we're here to help each other. The advise you were given in your old thread (two months and two weeks ago) hasn't been done yet. It's been my experience that if you ask for help, are given advise, and don't follow it, people will quit trying to help! Pull ALL THREE carbs, soak them overnight, blow them out with compressed air, and put fresh kits in them. There just isn't any "quick and easy" fix for this if the seafoam didn't get it.

Just my two cents worth. Sincere good luck wishes to you.

PS - You may want to run a compression check on her now.

Marc,thanks for the advice.I did work off advice from last post,however I started with fuel pumps and hoses first. Always start easy!

I simply am asking best easy way to remove "only" bottom carb as other two are fine. I prefer to not remove all three . I am sure there is a simple answer. No need to get aggitsted. Calming tones my good man.
Thank

Love Marc and all the great people here. I know Bill r very well. Sorry to waste your time.

No problem, not agitated. One of the experts may be able to pull one carb at a time, but the way the linkage is between the carbs for me it would make it "chancey" on screwing something up. Just tellin' my experiences, others may know a better way.

Have you done a compression test on the motor lately? This may tell alot about where you're at with the problem, not intended as a "poke".

Thank you. mark I thought you were mad at me .

yes check compression in it is good with me in 5 pounds of each other

sorry I am being a big baby just very frustrated with this carb
g

I would not advise only removing/cleaning the bottom carb. If one is dirty, pretty good chance the others have dirt in them too, afterall the fuel for all 3 comes from one source. Also, whilst you may thinkt he other 2 are ok now, how can you be sure since you get get engine above idle. If you are concerned about linkage, get a manual or at a minimum takes pictures before you tear into it

I agree you need to clean all the carbs, if you dont have a manual I can point you at a digital version to download free

You must verify that carburetors are clean on a " tower of power "

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A partially plugged carburetor means less fuel ( less cooling ) and less oil going into 2 cylinders.

Actually my old Merc Mechanic in Antioch CA advised me its very common for only the bottom carb to get the dirt and build up. He guided me on the easy removel. So I removed the bottom carb. First thing I noticed is no gas in float bowl chamber. It was totally caked with white deposits and gas was not getting thru screen . I broke down carb, cleaned, blew out and rebuilt. Perfect.

I put back on motor and when tilted now I am getting gas overflow from prime. the way it should be. I then removed the bowl side of top 2 carbs and they were clean with gae. Removed main float screws in the top two carbs on motor and cleaned out with air and carb cleaner.

Motor started and idle perfect. Brought up in bucket and power band seemed fine.

THAT IS UNTIL I DUMPED BOAT IN LAKE!

Could idle fine. However when I would try to power up it would bog and die. I again would let idle long time and squeeze of bulb showed full of gas. But when I would put in gear it would die.

Then I tried feathering the throttle and I was able to get it to finally catch and pick up RPMS I drove for about an hour at full cruise speed of 32MPH. I could go slow to but it would stumble some upon trying to hammer it again. Then when I turned off motor I would have to feather it again to get past stumble and power up.

My guess is there is a vapor lock, Air leak, loose fitting or something causing it to stumble unless I can manager to get RPM ups and then it gets past it. I have rebuilt fuel pumps. Checked every fitting I can. The only thing I may see is the fuel line to carb 2 in middle might be leaking as it appears gas may be on hose. I was not sure if this was from tilting motor and gas leaking from front of carb. Will replace line just to see.

Any other ideas?
Thnks!

Did you adjust the idle mixture screws with it running in the water ?? Turn them out a notch or 3 and see if that helps .

I fooled with just the bottom one. It did seem to help. Is there a proper setting for these?

Turn them all in till they just bottom then bring them out all evenly maybe 2 or 2 1/2 complete turns .Start it up in water and put in gear .Turn each screw in a 1/4 to 1/2 turn at a time on each carb .Keep doing this till it gets happy ..Try to keep each carb at the same setting .so when I said turn them in Do each carb only a 1/4 or half at a time not just one carb . Sounds like you could be running either lean or rich at idle and that can cause a Bog or flat spot when you hit her .

I think you are on to something. After I fooled with the lower one yesterday I was able to feather in into gear and power up. I will try your way today

Thanks for helping!

Ok Hope that helps . Im no Profestional Mercury Mechanic But I did stay at a Holiday Inn Last Night ...Let us know if that squares her away ..

Thank you so much Bobo, Marc S and everyone. Its running like new!

I got on water and did the adjustments as advised by Bobo on the idle mixture screws. That was amazing! I wonder if this has been an issue for the 8 years I have had this motor since doing a trade with my buddy Billr. It has always had bog or stumble when putting in gear and never would run slow well. Always had to run in upper part of power band.

Now I can put in gear smoooooth, and accelerate even up the band and even cruise from 5 to 35 mph with no stumble. Think this was the core problem and the carbs getting dirty was seconary. This probably luckily saved my motor from oil starvation and damage. Compression still excellent.

Thanks again!

Next project, remake the internal wiring harness as I can not find replacement. This one is held together by liquad black tape as its insulation is falling off.

Tod

Glad you got it all sorted out, Tod.

Im glad it worked for you .Didnt hurt cleaning your carbs either .Least you know thier good now . Good Luck and Have Fun !!
Larry