1984 Mercury 50 hp help with carbs

[anyquist]

Like stated I have a 1984 mercury 50 hp 4 cylinder 2 stroke outboard. I recently purchased the motor and have had a couple issues. The motor when started after sitting takes a little bit to get started but when fires up seems like it isn't getting the fuel it needs from one of the carbs and because of this possibly isn't running on all 4 cylinders. After idling for about 5 minutes I hear a noise that sounds like the other cylinders kick in, and I get back the power. The motor runs great after this happens, but when left to sit over night I experience the same thing every cold start.

I assume this is fuel related because the motor had sat around 7 years in my fathers shop before I purchased it from him. I since rebuilt both carbs. My friend who is a auto mechanic helped me with the removal of the carbs, and must have messed with the idle adjustments because after placing the carbs back on the motor after starting the motor it doesn't idle very good (want's to stall).

My questions:

1: what is a good starting point for the idle screws? I know for my other 2 strokes I start around 1 1/4 turns out and adjust from there. Is this the same?

2: I have read that there is another adjustment that will just adjust the throttle for both carbs.

3: is there top end adjustment on the carbs? I didn't see anything .

4:the image with the red arrow is pointing at the idle adjustment screw correct?



thanks

 

[ckangaroo70]

Re: 1984 Mercury 50 hp help with carbs

#1 About 1 1/4 to 1 1/2 turns out
#2 ?
#3 You do that by changing jet size
#4 You are correct.

 

[anyquist]

Re: 1984 Mercury 50 hp help with carbs

#1 About 1 1/4 to 1 1/2 turns out
#2 ?
#3 You do that by changing jet size
#4 You are correct.

Thanks for the reply, For the #2 question I am talking about throttle adjustment. Seperate from the slow speed adjustment. I have a tiller (not sure that it makes a difference) but I would guess that there is a adjustment screw near the throttle linkage that a person could tweak to increase idle speed of both carbs at the same time, once the air/fuel mix was right.

thanks

 

[79Merc80]

Re: 1984 Mercury 50 hp help with carbs

There is an adjustment. It's called "Idle Stop" Not sure where it would be located on a tiller model though. Just for your information, from idle to about 1/4 throttle, the carbs are not actually involved. It's all in the timming and advancing it. Once the timming is at full advance, then the carbs start opening thru WOT.

HTH, Craig

 

[motor dumb]

Re: 1984 Mercury 50 hp help with carbs

Hey yall I got a problem, just cleaned my carbs on my 1984 50 hp Mariner. all jets are clean needle in good shape but when I go to start it on full choke it starts good but when i take it off choke motor revs high for few seconds then dies .
I'm about to pull my hair out . please help

 

[ckangaroo70]

Re: 1984 Mercury 50 hp help with carbs

If you are certain your primer bulb, line and tank are good and you are certain that you have the low speed needle set rich enough...it may be the diaphram in your fuel pump is dried up and not wanting to pump fuel very good on its own. Although it may also just be that you didn't get the floats set quite right. Whatever the problem...it definatly sounds like a fuel problem and I would start at the tank and make my way clear thru the fuel system inspecting each component. Make sure all your lines are good and clamped well with no possible air leaks and make sure all the screws used to put your fuel pump together are nice and snug with no possibillity of air leaks. Did you use compressed air to blow out all the passages when you had the carbs off? Sometimes just using a carb cleaner can release deposits that can plug up a passage. So its good to use compressed air to blow everything out good before reassembly. I know that sometimes it can be aggrivating tracking down the culprit, but hang in there.

 

[aussieflash]

Re: 1984 Mercury 50 hp help with carbs

motor dumb,start your own thread for better response.Hijacking is a federal offence.