how clean should carb be?

[medic2051]

'75 johnson 50 hp was running very rough at low speed. Figured carbs must be gummed up, so I took 'em off and opened them up to clean and rebuild. They look pretty clean to me. Not really any varnish. My question is, how dirty do they have to be before they start to cause rough running. If not a carb problem, then what?

 

[The Marine Doctor]

Re: how clean should carb be?

Idle problem could be linked to compression, lean pop<--carbs or the sync and link is wrong.<br /><br />As for the low speed jets..blow them out with compressed air. You might want to remove the welsh plug on top to see if the holes are clear for the fuel to go through.<br /><br />TMD

 

[medic2051]

Re: how clean should carb be?

To re-sync the carbs, is it necessary to use a timing light, or will hand adjusting the links suffice.<br />And, what is a welsh plug, and how do you remove it.<br /><br />Thanks

 

[The Marine Doctor]

Re: how clean should carb be?

Sync and link requires a manual.<br /><br />The welsh plug is the grey frost plug on top of the carb.<br /><br />TMD

 

[Solittle]

Re: how clean should carb be?

And your homework assignment is:<br /><br /> http://www.outboardrepairs.com/carburetors/

 

[medic2051]

Re: how clean should carb be?

Yea, yea, I read them. Just hoping to gleam a few more tips fom those who have been down his road. Actually I was hoping some one would say that even if they look clean, any small little fragment could cause the engine to run rough.

 

[ob]

Re: how clean should carb be?

And it can.If your fixed orifices,bowl pickup tubes, or passages have any gummy deposits in them ,compressed air will not get it out.You can use a set of indexed torch tip cleaners to insure the pickup tubes and orifices are clear,and soak the carbs in cleaner if you suspect porting or passages are gummy restricted and then follow with a blowout with compressed air.Restrictions as small as a few thousanths of an inch can cause significant performance issues.When it comes to fouled carburetors an ounce of prevention is truly worth a pound of cure.Good luck

 

[OBJ]

Re: how clean should carb be?

And it could Medic...don't take much. When you rebuilt the carbs, did you remove the jets and clean them individually and blow the carb passages out with air?<br /><br />But there are a few other things that can cause a motor to idle rough.<br /><br />As the other gents posted, sync and link can be one of them. The idea behind sync and link is to put the timing of the engine and throttle plate opening in sync at a particular place.<br /><br />Poor ignition on one cylinder can also cause a shakey idle. Your spark should be able to jump a 7/16 inch gap with a hot blue/white spark. If it don't, could be the problem.<br /><br />Is there any blow back from the carbs at low end....meaning, does any one carb seem to be blowing out instead of sucking in? This means a damaged reed. Look for excess fuel/oil mixture laying about the cover.<br /><br />This should keep ya' busy for a while....keep us posted....thanks.

 

[clanton]

Re: how clean should carb be?

If you spray water or spray can carb cleaner in the right spot, the fluid will flow thru the passages, and you will not have to remove the welsh/core/freeze plug

 

[medic2051]

Re: how clean should carb be?

nice tips. Thnks to all of you.