Carb. Sync.

[sweaver]

Can anyone give me a straight forward way of adjusting multiple carb. setups. Most of the manuals I've refered to don't go into any detail on this. I'm afraid using the "ear" method is not what the factory had in mind. I'm afraid this leaves too much room for error. Also, can anyone give me some help on looking up service bulletins. On an earlier post some of the help refered me to service bulletins pertaining to my specific model. I did a search but maybe I'm just not familiar with how to properly enter the search.

 

[WillyBWright]

Re: Carb. Sync.

Wutcha Got?

 

[sweaver]

Re: Carb. Sync.

I'm currently working on a '92 60 hp Evinrude(3 Cylinder) but wouldn't it be basically the same on any others?

 

[DHPMARINE]

Re: Carb. Sync.

You can never really know what the factory intends or expects.Engine tuning by ear has gone by the wayside.Back when we had adjustment screws for mixture,yes the ear worked.All you needed was a feel for smooth and highest engine speed,then the knowlege of weather to set it a tad rich or not.<br /><br />Your 3 cylinder engine actually has NO CARB adjustments.So ears are out.(you could rejet it if needed,but this is seldom called for.)<br /><br />What is adjustable is the relationship of the carb throttle opening of all 3 carbs and the timing.For this adjustment you need the factory manual,I don't know of any other way.<br /><br />DHP

 

[duke3]

Re: Carb. Sync.

Well SF174.<br />Your carb hase needle valves for Slow speed adjustment.<br />Make a link and sync, and adjust the carb needle valves according to the manual.<br />But your manual will say, idle speed shall be apx. 750 rpm. My 60HP VRO from 1990 wont run at that low rpm. So my idle speed is apx. 1000 rpm in gear.

 

[sweaver]

Re: Carb. Sync.

The carbs. I have do have some type of adjustment located on the left(facing them) top at a 45 to the carb. intake. I figured it was low speed adjustment. duke3: as you said this motor does not idle at the factory setting. I did have to idle it up a bit. I guess what I'm after is how do you tell (for sure)since the motor is ruuning while you're doing it that the carbs have been set properly. When you start adjusting each one you can tell a difference in how the motor runs.<br />Here is how I do it: turn each adjustment out 1 1/2 turns. start and let warm up. start on top carb and adjust screw CCW until motor runs too rich(stumbles) then CW until too lean(skips) and then split the difference. Go to the next carb. etc. It is hard to notice a difference in the way the motor is running sometimes. I was after a better way that might be more precise.

 

[andy6374]

Re: Carb. Sync.

Duke3-<br />If you have to run 1000 RPM's in gear at idle, I would take a look at your reeds next time you get a chance. 1000 RPM's in neutral at idle is ok, but not in gear.

 

[duke3]

Re: Carb. Sync.

Well andy6374, all the reed valves have been controlled, and found OK. New plugs, Disconnected VRO pump and mix 50:1, comp. test was 108, 110, 112 PSI. After that, my Marine shop did make a link and sync and adjusted carb.<br />At idle I can read apx. 1050-1100 rpm, and idle in gear I can read apx. 975-1000 rpm. Motor starts first time, and runs great. We did try to adjust it below 950 rpm, but then it will slowly ( apx. 1 min) die.<br /><br />Well SF 174, back to your motor. You are doing the right kind of adjustment on the carb, but first you must be sure, that the link and sync is 100% sure, and you are using the right and good plugs (QL77JC4 gab 0,3" to 0,4". 0,4" will give you a better idle !!!!!!!) <br />After that, you can adjust the carb as you already have tryid. After all carb have been adjusted, the readjust them all again.<br /><br />If the motor still not will idle, then you have a comp. problem, leaking problem or ???