choke issues?

[mmscottmhk]

my 84 90hp has to warm up a good 3-4 min before it will run in gear but after that it idles fine until you try to go fast then it tries to die unless you push the choke then it sputters but revs on up to speed. then after you park it to get the trailer you have to go through the whole process again which is no big deal unless there is someone waiting on the ramp! any ideas?

 

[Texasmark]

Re: choke issues?

For starters get some Sea Foam at an auto parts store and add a 16 oz can to your standard 1pt oil to 6 gal gas mix. Work the whole tank through the engine. If that doesn't fix it you might get some carb kits and put them in ensuring that you thoroughly clean out your carb jets and all in the process. Assume you have fresh, clean, fuel.

Mark

 

[Chris1956]

Re: choke issues?

Sounds like your carbs are dirty or the idle mixtures are set too lean. The seafoam may work, but more than likely it will not.

 

[Dave1027]

Re: choke issues?

Open up the idle mixture screws till it idles and accellerates properly.

Edit to add: sorry for the double. I see Chris already posted that.

 

[mmscottmhk]

Re: choke issues?

does anyone think this could be caused by a bad fuel line?someone told me that when you push in the key that it sends a pump of gas to the motor which is what i thought was the choke. that made me wonder if it was starving for gas when i throttle up. when i give it gas it boggs down until i push that button then it revs up like it needs a little help getting the fuel up there. Could it be the pump ball?

 

[Dave1027]

Re: choke issues?

Where is the head bang icon?

 

[mmscottmhk]

Re: choke issues?

i know i know but everybody tells me if you aint a mercury mechanic dont turn no screws or it may never run the same. and even though i might consider doing it anyway i dont even know which screw it is.

 

[Dave1027]

Re: choke issues?

Those carbs only have one adjustment screw. If you are worried about getting them wrong, carefully turn each one clockwise till it closes and note how many turns. That way you can always get it back to the way it was. A good place to start is to add a half turn to where it was should take care of it.

 

[aussieflash]

Re: choke issues?

First check enrichner/choke valve is working,pump ball firm,pull lower hose off valve and push in key...should flow,then release key and flow should stop.If not replace valve.
Now check fuel pump and diaphragm.Then remove carbs for servicing/new needle/seat and gaskets.Reset floats to spec....makes a huge difference.

 

[mmscottmhk]

Re: choke issues?

should all of the adjustment screws be set the same because there is some difference. the bottom one is out farther than the top two.we are talking about the big silver screw on the front right?

 

[Chris1956]

Re: choke issues?

Carbs usually have different adjustments for different carbs. Normally the upper carbs have a richer fuel mixture.

 

[Texasmark]

Re: choke issues?

The only adjustment, the low speed is on the port (left facing forward) side of the carb. They are brass with a SS spring on them. Be very careful when you turn them all the way in (seat the pin) to start your back out counting. The brass is soft and you can score it if you get it too tight. 2 fingers on a small screwdriver and when it stops you stop. If you score it, it's almost impossible to get it set right.

Mark

 

[Dave1027]

Re: choke issues?

should all of the adjustment screws be set the same because there is some difference. the bottom one is out farther than the top two.we are talking about the big silver screw on the front right?

Sounds like the idle mixtures are out of adjustment. Do it this way. Set all screws to 1 &1/2 turns out. Start the motor and one at a time, begin slowly closing the screws till the motor begins to stumble then turn out the screw 1/2 turn. Do all carbs that way then test accelleration. If it does hole shot smoothly then open all screws an additional 1/4 turn.