1984 25hp manual start Question on knob???

chunkin

Cadet
Joined
Nov 6, 2008
Messages
14
Friends,

There is a knob right next to the carb, what is the purpose of that knob???

When my motor has a hard time starting, I turn it to the left (counter-clock- wise) and it starts better and idles better.

But I have been told that afterwards, I need to turn it back clock wise????

Thanks for the help,

Chunkin.
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,721
Re: 1984 25hp manual start Question on knob???

If you are referring to #29 in THIS DIAGRAM then it is the slow running mixture adjustment. Turning it anticlockwise will enrich the mixture

Set the adjustment to best slow running according to the instructions in Joe Reeves article on carb needle adjustment on the Engine FAQs board, (top one in the "Repair and Maintenance" index)
 

asdasc

Senior Chief Petty Officer
Joined
Aug 28, 2008
Messages
681
Re: 1984 25hp manual start Question on knob???

Just a personal pet peeve, maybe you can help me with it...I wish the Engine FAQ was in an easier place to find for new users. Or least in a place that was easier to describe when sending people there.

Many of the questions that come up are in the FAQ, but most people new to the site can't find the Engine FAQ.

I am sure that 90% of the people I send to the FAQ end up clicking on the FAQ link in the tool bar between User CP and Members List.

Maybe we could pin a link to it at the top of the forum?

just my 2c, sorry!
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,721
Re: 1984 25hp manual start Question on knob???

You are quite right. It's an initiative test for newbies!

Seriously that is why I either give some indication as to location of the engine FAQs or give a direct link to the item in question.

So for my post above I could have said .... in the engine FAQs HERE
 

chunkin

Cadet
Joined
Nov 6, 2008
Messages
14
Re: 1984 25hp manual start Question on knob???

Yes, it is # 29 Vic.

What do I do?

chunk
 

chunkin

Cadet
Joined
Nov 6, 2008
Messages
14
Carb Needle Adjustment (how)

Carb Needle Adjustment (how)

Friends,

I went to FAQ's, but it says nothing on this. One post, but the link did not work.

How do I know when the carb needle is properly adjusted on my 1984 25 hp manual start?

Chunkin
 

asdasc

Senior Chief Petty Officer
Joined
Aug 28, 2008
Messages
681
Re: 1984 25hp manual start Question on knob???

OK, that is awesome! I gotta learn how to do that!

link
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,721
Re: 1984 25hp manual start Question on knob???

What do I do?
You do what I suggested you read Joe's instructions for adjusting.

You pull the knob off the screw and adjust the setting following Joe's instructions using the screw driver slot in the end of the screw (if you can get it running OK there is no need to seat it and screw it out 1.5 turns you can skip that bit) When you have it adjusted refit the knob in its mid range position.

If it helps you can twiddle with the knob when starting but return it to its mid position once it is going.
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: Carb Needle Adjustment (how)

Re: Carb Needle Adjustment (how)

Poor instructions and confusing links. The Engine FAQ as opposed to the FAQ above. It's listed as a separate forum located here: http://forums.iboats.com/

Its link is here: http://forums.iboats.com/forumdisplay.php?f=31

And the link to Joe Reeve's instructions is here, with someone else's name on it. ??? - Go figure. http://forums.iboats.com/showthread.php?t=167352

If the carburetor is clean and the engine is running rough, ease the choke on a little. If adding choke causes the the engine to run faster and smoother, you are running too lean and need to get more fuel in the fuel air mixture.
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,721
Re: Carb Needle Adjustment (how)

Re: Carb Needle Adjustment (how)

Firstly dont start a new thread on the same topic.

If you cannot follow the guide I gave click on the link I put in later that will take you direct to Joes instructions > If you cant do that then here they are:


(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

Note: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Carb Needle Adjustment (how)

Re: Carb Needle Adjustment (how)

double posting is not appreciated. merged threads.
 
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