carb adjustments

[albass]

Which way and what screws do I turn to richen up the mixture on my 1985 75hp motor seems to be lean from what people are telling me?

 

[jimalsk]

Re: carb adjustments

To richen the mixture turn screw counter-clock wise. To lean it turn clock wise. The needle screw is on the right hand side looking at the face of the carbs. Normal is 1 1/4 turns. Turn each one the same amount of turns. Have the motor running at idle in the water,in nuetral. Get it to operating temp. then have at it. Turn counterclock wise slowly till the motor starts to stamer a bit the turn clock wise just a bit till it smooths out. Do the same with the lower carb. I have the same motor.Mine are out 1 1/2 turns. Run it for a while on the lake or river and check the plugs to see how they look after you adjust. Remember to put the air box back on and cowling before you take it out. Good luck

 

[jfholijr]

Re: carb adjustments

Hey alaska river runner, does your motor idle a bit ruff or shakey? I've rebuilt everything and made every adjustment and still does not idle smoothly. At WOT it's a different story, smooth and strong. I've seen others with these 650's and they are able to get there's to idle smooth. Kindof got me stumped. <br />Any suggestions?

 

[jimalsk]

Re: carb adjustments

It idles so smooth jello won't wiggle

 

[WillyBWright]

Re: carb adjustments

The only thing I'd like to add to Alaska's procedure is to have the motor in gear. It'll help with getting a good idle speed. Sometimes if you get a good low idle out of gear, the motor will die when you put it into gear. That's about the only advantage. But yeah, you should be able to get a smooth idle from that motor.

 

[jfholijr]

Re: carb adjustments

Well I've replace fuel tank, bulb and line, rebuilt fuel pump, properly cleaned and rebuilt carbs, did the link and sync correctly, idle screw adjustment was done with warm engine - in gear at idle speed, I have good spark on all three cylinders and compression is 150 on all three. What else can I do to smooth this puppy out?

 

[jimalsk]

Re: carb adjustments

Whoohoo what is the idle RPM on your motor now??

 

[jfholijr]

Re: carb adjustments

I've tried 650 through 950. Right now out of gear it will idle at 1000 rpms, in gear it will drop down to about 700.

 

[jimalsk]

Re: carb adjustments

Mine idles around 950-1000rpm's. I don't run a prop on mine. It's jetted. Next time you take it out watch the tack. and see at what rpm's she smooths out at. Sorry I can't be much help although you have given me some food for thought while I'm at work counting salmon this week on this one.

 

[real550A]

Re: carb adjustments

Hey Alaska! What river do you run?<br />My brother lived in Manley for many years, and had fish wheels.

 

[jimalsk]

Re: carb adjustments

Real550A, I run a few here in South Central Ak. The Big Susitna,Lil Susitna,Deshka,Talkeetna, Clear Creek just to name a few. If I can keep the lower end of the jet wet I can run it.