Still Stumbling!

Ok I wanted to start a new thread for this because I think we gotten a little off course.

My 86 3.0l is still stumbling or hesitating coming off idle, I worked on it all weekend spent plenty of money and it is better but still not fixed.

I started with the basics new points, condensor and spark plugs all properly gapped, set the dwell, and adjusted the timing. Problem still there so I attack the fuel system... New fuel filter, replaced the intake gasket adjust carb. problem still there. I found the coil had been wired backwards so I changed it around runs much better still wont take the fuel off of idle. I remove the carb and disassemble it when I have a "Eureka" moment the inlet ball and passage under the the acc. pump was completly blocked and the venturi cluster mounting was warped causing it to not seal. I clean everything replace the venturi cluster reassemble and install. The engine cranks good cold comes up to temp readjust carb idle is smooth hit the throttle and she falls on her face. I back out and bring her up slow at about 1050-1100 rpms it will take the fuel no hesitation.

I am at a loss I really don't understand what I'm missing any thoughts?

Also the timing tab on this engine is badly corroded does anyone have a pic of what it should read I can make out all the notches and 12 and the word before but I'm not sure which notch is tdc.

The idle circuit cleaned ,you soaked the carb, removed the jet, blew carb cleaner thru, and and compressed air ?

The float is set correctly ? Bend it a tad so you have more fuel in the bowl.

All put back together still doing it ? If yes spray carb cleaner around the base of the carb, see if you have a vacuum leak do it with the motor running around 1200 rpm.

I re-read the post again, the accel pump is new ? it fits snug ? Same as the one you changed out?

You do know this ain't a race boat i always give slow easy gas when i want to get on plane.

I got the exact same motor and drive as you.

Today i dragged the boat around the front of the house and had her started in a hour. I five years ago re-built the carb, i had to go back in after the first time on the water and bend up the float to give a little more gas in the bowl. Never a problem after that.

Yeah I realize its not a race boat but it should be better I lived with it last year but its tough on skiers. Yeah I bought the sierra carb kit this time instead of the one from the auto parts store. I blew soaked and blew through every passage in this carb. Its really aggrevating. I know the idle adjustment should be done on the water in gear but roughly what should it run on the trailer in neutral?

Ok chief scratch the last post I went back out and noticed that I'm not getting my accel pump spray until it reaches half throttle so I bent the rod until it starts spraying right off idle and she come up like a "race boat" but it puts my pump plunger too high or something it wont refill after the one shot. whats up with that?

I read the entire page, I just don't see any info on when the pump should start spraying. I did find an old delco rochester manual on the 2G carbs and it says that the inlet ball under the acc pump is aluminum. I'm thinking the one I took out was aluminum but the carb kit I have has 2 steel balls one for the inlet check and one for the discharge. I am fairly confidant that I'm on the right path with this now it accelerated to good when it sprayed immediatly off idle.

Any thoughts?

i'm drawing a blank. Something jamming the accel pump or the linkage. The spark arrestor it hitting something ? The wires holding the spark arrestor ?

I thought about this all day believe it or not.

My friend who i will see this afternoon cause he's working i'm gonna ask him.

I very much appreciate the advice... Nothing seems to be hitting the linkage it moves freely, it seems to have been this way at least since I have owned it. I have a theroy... Because I do injector pumps I understand effective stroke. There is a slot cut part ways down the barrel of the pump so until the cup of the pump passes that slot any flow will go out the barrel back into the bowl after that the rest of the stroke is sent out of the nozzle. It seems the plunger is set too high so the throttle shaft is at 1/2 or better before the cup passes the slot. but measuring by the specs it was set correctly. What I think may have happened is when I adjusted it to come in right off idle the cup is not coming up above the slot allowing the air to purge out of the barrel. It almost seems that I have some incorrect parts with this carb...
I don't know just a theory... I check back to see if your friend knows whats going on.

He actually said you have a wrong part. I just assumed you got the right kit.

It is very possible someone has swapped carbs. I'll tell you what I did may not be the correct solution but it seems to be running right I'll know more when I put it on the water.

If you remember I have the carb off of my 2.5L but its bad trashy. So during the rebuild i stole the venturi out of it. Anyway I pulled the top off of the one thats on the boat unhooked the pump and pushed it down into the bore, the spring on top was weak, the pump rod went down but it did not press the cup down so I looked at the old carb it has the same length pump but the spring is stronger.

I swapped springs and pushed it down into the bore again now the return spring is too weak. the plunger wont come back up. I pull the plunger back up and the cup comes off the end of the plunger.

So I took the original spring off of the top of the pump and used it as the return spring. Put it all together and it works. Maybe not the way it is supposed to but it does work.

Not sure my next course of action whether I should embrace the Jerry Riggin' or try to find the correct solution.

What do i know, i took the mani, riser, and carb all in one piece and put it on my 86' merc motor 140 and it runs great. The old motor was a 2.5.

I rebuilt the carb when i first got the boat,and had to open it and adjust the float on the water when it had the 2.5 and actually after sitting for 8 years before i got it, the motor started 1/2 hour after i had it in my driveway.

I put a new fuel pump, riser, and starter on it. New impeller and housing.The year after i put a new alt.

Back to the carb i do wander in my posts don't i.

I have the original package of the kit i bought 6 years ago.

It is Mallory
9-37616
19029

Above is exactly the way it appears on the side sticker of the box.
9-37616 is on the other side says part number.

Kurt i can't seem to find the receipt, not like me i usually put them in the box so i can;t say where i got it.

I wish i can help more.

The place where I ordered my kit from showed that part number for the 2.5L and a different number for the 3.0L. Who knows I may order that kit and see if I can do something with my old carb.