60 hp mercury 2 stroke 3 cylinder Stumped HELP!!

[Dallas1989]

when i would start the boat with fast idle lever up it would start and run pretty decent if i let the lever down the boat would stall so i adjusted the idle got it too where it idled good when i put it in gear the boat would die instantly so i pulled the cover off again and found out the top cylinder is dry no fuel getting to it the 2nd and 3rd cylinder is wet with clean plugs the #1 plug is black im getting spark on all 3 cylinders compression test is 130-132-136 i pulled the carb's completely apart and cleaned sprayed carb cleaner thru all the jet's and holes im literally lost at this point timeing is fine or the boat wouldn't run so good on 2 cylinders and suggestions will help..

 

[danalex]

I had a similar problem 2 days ago. My bottom cylinder was not running, was dry, then after carb clean was too wet. After checking and trying everything else, I cleaned out the lower carb again and found a tiny chunk of trash in the idle speed adjust needle screw. I recommend you take both needles out and spray the holes good, also clean needle with spray. Best of luck.

 

[Dallas1989]

yeah i did that exact samething u have a 88 2 stroke 3 cylinder?

 

[danalex]

mine is a 1986 2 stroke 60 hp mercury 3 cylinder. Had set up a couple years it looked like.

 

[Dallas1989]

Dana when ur boat is at idle is both carb plates closed? or are they opened a bit? cause i bench synced mine and its been a problem every since 1 was opened a little more then the other

 

[danalex]

They are both closed. I checked several times to make sure, cause that would make it run faster. Good thought and I will check again just to make sure.

 

[Dallas1989]

yeah im out of options with my motor i dont know what else too do i've took the carbs off 5-6 times and re cleaned them still dry on top cylinder

 

[Dallas1989]

okk after adjusting the carbs and doing another huge cleaning on the carbs im visually seeing fuel spray out the top carb so that is a + boat is running outstanding the top plug is getting a little wet now so im getting fuel there another huge + but the plug is still black could that be due too running rich or lean?

 

[danalex]

congratulations! The two needle valves in the face of the carb adjust your idle mixture. Tighten down to lean out or decrease fuel, loosen to enrich mix. I personally do this: count the number of 1/2 turns it takes to lightly seat the top carb needle. Do not overtighten it. This is good info to keep, you can always get back to this start point now.
With the boat in the water and in gear, without anyone near the prop (not even in the water, this is the #1 boat accident) starting with the screw at the original setting, tighten it till you hear the motor running rougher. Take note of where that is. Now loosen it past its best running position, till it staggers. Halfway between these two points is the sweet spot, then maybe! back it out another 1/4 to 1/2 turn. Then do the same for the other carb. Hopefully someone else will chime in to correct me and you will get the correct method from them.

 

[Dallas1989]

alright danalex where do i adjust the idle cause it will still die down when i let the fast idle lever completely down thats my only problem im haveing atm i have the idle stop screw bottomed out and it still idles way too low it gets down too 200-300 rpms and dies maybe lower

 

[danalex]

I would take the throttle cable loose at the motor - loosen the phillips head screw till you can move the tab that holds the throttle end in the hole, move it to the side and carefully take that cable loose. Now you can work with the motor without having to run back and forth.

In the face of the carb are those two slow speed idle adjust screws, one per carb. You already know about them. One or both are almost certainly too rich, that is unscrewed too much.

Start the motor and work the throttle at the motor to keep it running. Once it is stable and you can turn loose of the throttle arm: With the motor running -
If the top plug shows wet start with the top carb. Tighten the idle adjust screw 1/4 turn and stop, listen. Give it a couple seconds for lag. If it speeds up, push throttle arm to lower the rpms. If it runs worse, turn the screw the other direction, wait a couple seconds and see what happens. if No change: adjust more same direction. If it runs better: adjust more same direction. If runs worse: stop! go the other direction, repeat. Once you get the best range, try to stop the screw in the center of that range, then do the other carb the same way. I will go back to carb one after I finish carb two, I believe the center cylinder is fed from both top and bottom carbs.

If the magic happens and you get it where you want it that is great! Now you need to take it to the water, and while you are not in the water around that killer prop, have it in gear at low speed and redo the low speed adjustments. It will act different once you have in in the water because of the back pressure of the water in the middle section of the motor.

Please let me know what happens!

Dan

 

[Dallas1989]

Dan i adjusted the idle screws as u said and the boat runs really good only problem im haveing is i cant adjust the throttle cable too where the boat will not cut off i have it maxed out and it still lets the boat idle too low and cuts it off

 

[danalex]

Then (IMHO)you need to adjust the throttle roller at the top of the carbs. Right now it must not be touching the accelerator at idle, and butterflies are hard closed. Back off your idle screw about halfway and adjust that roller it so it is touching. There is a small flat head screw that holds the cam to the shaft through the carbs. You can see this screw from the port side (driver side) of the engine if you remove the plastic tubes thingy - I have no idea what that is called, it is held on with 2 7/16 head bolts. You loosen that screw and you can move that cam. It takes an amazingly small amount of butterfly open to give you a lot of throttle. Make sure both butterflies are moving together. I think the manual calls for .005 to .040 clearance between that cam roller and the throttle part it rolls against at lowest idle. I am still waiting for someone knowledgeable to correct this, and would be happy with that.

 

[Dallas1989]

i have that adjusted too the closest point of touching the accelerator i cant adjust it anymore im so close too get this thing running perfect but i feel like im weeks off still lol..

 

[Dallas1989]

its in a slider type thing on the top of the carb correct?

 

[Dallas1989]

alright so after working on it today i found out the top cylinder is fireing as supposed too but the 2nd and 3rd cylinder the plug is soaked with fuel too the point its washing the carbon off the piston aswell as the plug its very clean and shiny is there a way i can hook up a carburator syncronizer gauge too this engine? so i can figure out the vacuum that these 2 carb's are pulling cause somethings off

 

[danalex]

yes - if that slider thing touches the roller at the top of the carbs it will open the butterflies. That will idle the motor up. You will have to readjust the idle speed screws to allow for the extra air. If that is adjusted right though, you should adjust the timing at idle to make it idle faster. Be careful to make note where it is when you start so you can go back if you need to.

The proper way to control the idle speed according to a mechanic on another forum is to adjust the spark advance. That is controlled by a screw just like the idle screw on the throttle arm. The top screw is the max spark. The second is the...max throttle, I think, from memory. The third screw controls the spark when the throttle arm is at rest, it works against the spring in the throttle arm such that when you apply throttle, the butterflies open, you apply more throttle, then the spark advances. If you unscrew this screw the resting spark will advance. It should not take very much movement to make a difference.

 

[danalex]

The mechanic I mentioned is on this forum, jmmbo. He posted a link to a manual with the disclaimer it is not the original manual. I will share this link, it has the tuning info on our motor on pages 240 and 241. I think my timing is ok, but I will go get a timing light, borrow if I can, and check to make sure. I printed those 2 pages.
http://162.144.28.33/lib/mercury/man...-115.html#/240

 

[danalex]

I think you need to look at the spark advance now and see if you can idle it up with the spark.

 

[flyingscott]

Are you sure you do not have water intrusion?