1994 20hp cold starting issue

[hardwater fisherman]

I have a 20hp mercury serial number G234977. When I first got it back when it was still warm, I did not have any cold starting problems. The manual says to turn the primer knob to the right and fully pull it out twice waiting 5 seconds between each pull. Then leave it out until motor starts and then push it in once started.Then when warmed up turn it fully left. The last 3 outings the air temp was close to freezing and water temp in the 40s. I used the same starting procedure and it started 2nd or 3rd pull, but it would stall after around 30 seconds and was hard to restart. I found the only way to restart and get it to run was to turn up the idle with the brass colored screw. Then after it has warmed up turn the idle screw back down. I know this is not ideal but it worked. What is the most likely cause of this problem? I have no other issues with the motor. It runs well at all speeds once warmed up. And it idles down really nice too once it has warmed up. Thanks in advance for any help. EDIT By the way this morning I started in the driveway and I left the primer out after starting and that only made it stall quicker than if I pushed it in.

 

[GA_Boater]

With cold water and air, the motor will take a few more minutes to warm up. The motor may not be fully warmed up when you turn the primer left. I would give it a little more time.

Can't you use the throttle for a fast idle instead of changing the idle screw?

 

[hardwater fisherman]

I leave it all the way turned to the right but it stalls anyways. As far as throttling up with the tiller there is no "travel" on the tiller handle. When in neutral it does not allow one to rev it up. I think that is why there is an enricher so it gives it more gas until warm?

 

[GA_Boater]

I was thinking side shift, not tiller shift. Oooops.

 

[hardwater fisherman]

This set up is new to me so I have no experience with this type of carb. I have always had choke flappers and the option of throttling up in neutral.

 

[flyingscott]

Turning the primer to the right is the high idle adjustment for starting. Take the hood off and turn the knob, does the rod move the stator? That has a plastic linkage that likes to break. Also when you start it leave the primer out until the idle starts to drop off then you can push it in. That is the same as leaving the choke on for the warm up

 

[hardwater fisherman]

No Title

I just went out and looked and I am missing the rod that comes off the fast idle lever. Number 8 in the diagram. The fast idle lever does not seem to be broken. Are you saying it likes to break at the other end? I dont even know where the rod attaches. In photos I looked at it seems to go under the flywheel. Also how much should the black plastic fast idle lever move when turning the primer knob? I ask this because when turning the knob it barely moves. Or is this because the rod is missing? I tried leaving the primer pulled out after starting and it stalls quickly after it starts. And then it becomes hard to start after.

 

[flyingscott]

It likes to break at the linkages on the carb. They are only plastic so it happens the rod may be floating around in the motor somewhere. Here are some pics of mine should be similar. Not having the rod in place is probably causing the hard starting. Sorry the pictures aren't the greatest.

 

[hardwater fisherman]

Thanks for the photos. I was not able to find the fast idle wire. I did make one from a handle off a small bucket. Where it connects on the carb end is straight forward. On the trigger end I was not sure. Behind the ball and socket on the spark adjustment link. There is a slot and I hooked it in there. Is that correct? What is the function of this rod? Does it hold the fast idle lever from moving? It is not quite as cold today but it started well and stayed running. And it restarted well also. I adjusted the rod according to the manual. Also before If I pulled out the primer while running it would stall right away. Now it takes several seconds before it stalls, which I think is normal. The only thing is turning the primer knob has little to no effect on the idle speed. My nephew has a 9.9 merc and the knob says turn for fast idle. On mine it only says pull to prime. Thank you for the help.

 

[flyingscott]

Yes behind the ball is where it hooks up. The rod when connected to the knob will pull the stator forward for the high idle turning the knob to the right is the high idle. You should see the throttle assembly move when you turn the knob you may need to put a bend in the rod to shorten it up. Use your nephews 9.9 motor as a guide as it is the exact same set-up. Make sure all the plastic pieces on the carb are in good shape and not broke.

 

[hardwater fisherman]

Ok thanks I will have to take a look at my nephews motor to see how it should work. As you say something could be broken. When I turn the knob it moves up and down in the grove of the fast idle lever, and the spring on the side expands and contracts. The primer lever moves up and down, but the only time the fast idle lever moves is when the primer is pulled fully out.

 

[flyingscott]

The plastic pieces can break on the carb. When the knob is all the way in and you turn it to the right the lever should move.

 

[hardwater fisherman]

The lever is not broken but is badly worn in the slot. I can pull it back and it will stay, but turning the knob will not pull it forward. Even if I try to pull the stator forward it does not move. If I remove the link it will move back. So what I am saying is that it is adjusted fully forward. Maybe this is what caused the wear on the lever?

 

[flyingscott]

Are you pulling the knob out first and then turning it if so it won't work correctly. With the knob pushed all the way in turn it to the right and see how much movement you have.

 

[hardwater fisherman]

No Title

I am turning it with the knob pushed in. And the primer lever moves up and down but the slot is so warn in the idle lever that it stays stationary. I added 2 photos one is a new lever and the other is mine. It might be hard to see but mine is almost worn through on one side.

 

[flyingscott]

Yeah that does look bad replace it and it should start working correctly. The idle wire is also available new less than $10. I also lube that slot up with some grease once a season.

 

[hardwater fisherman]

I am going to try to find a replacement and I will pick up a new idle wire also. I will be putting it away probably after next weekend so I will have all winter to fix it up. Thank you.