messed up my carb!!!help

[rob711]

well i rebuilt mt carbs for my 1984 90hp johnson today put them on and.....it now runs worse then ever...i'm thinking it was the mechanics fault...that would be me!! the motor will sort of run if i keep choking it, something i never had to do before...i'll try again but i'm assuming that i screwed up something inside the carbs....i shot carb cleaner through every hole from both ends replaced the float and needle valve and seat, replaced the gaskets...well hey it dosent leak!!!clearly i screwed up any ideas...it seemed clean..but

 

[iwombat]

Re: messed up my carb!!!help

Pull 'em apart again and check your float level.

Another possibility:
If you didn't totally disassemble everything, and just zapped 'em with cleaner you may have just blown gunk down to the next orifice in the chain. That's why complete disassembly and soaking is really the only way to approach a carb rebuild.

 

[jtexas]

Re: messed up my carb!!!help

You can check the operation of the float valves before installation by blowing into the fuel inlet. Carb upside down, no air should pass; right side up, might be a little resistance but not enough to make ya blue in the face. Hope you like the taste of 2-stroke mix.

Double check the routing of your fuel lines. Make sure you got gaskets everywhere there should be a gasket.

Did ya take out the core plugs & shoot carb cleaner through all those holes?

 

[Joe Reeves]

Re: messed up my carb!!!help

There are two (2) fixed brass high speed jets located in the center bottom portion of the float chambers (in back of those screws on the side). If you didn't clean them manually (all 4 jets - 2 carbs), do so with a piece of single strand wire.

The idle air bleed jets that screw into the top portion of the upper body should be marked 34 which indicates a ID size of .034.

The small intermiediate jets that screw straight down into the lower body (float chamber) should be marked 26 which indicates a ID size of .026.

Did you by chance mix them up? NOTE that the sizes may be slightly different BUT the larger size goes to the upper carburetor body.

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

The linkages between the carburetors should be set so that both carburetor butterflies open and shut at the same time. Double check that.

The carburetor roller should contact the scribe mark on the cam when that roller is dead centered with that scribe mark, not before or after. THis is when the throttle buterflies just start to open.

Let us know what you find.

 

[rob711]

Re: messed up my carb!!!help

the only jet i removed was the one with the float...i sprayed the jets that come out through the middle of the bowl assembly..i'll try putting a small wire through...i blew air through the passage way that the fuel line connects to and that valve seems to be doing its job..i also drilled a small hole in those plugs and cleaned out in there....i think they are the idle jets?...any way they were clean. every thing seemed to be clear ...(which is why this is frustrating...yah boating!!!) i replaced the plugs with new ones from the kit...i never checked for leaks on them, i'll look at that too...thanks every one..any one else want to add i'll gladly take the advice

 

[rob711]

Re: messed up my carb!!!help

well i took my time with the carbs yet again and sucsess...it run smoothly with the muffs on..i did a cylinder drop test by pulling off the plug wires...the top 2 cylinders there is a noticable drop in rpms, but not so much with the bottom 2.there is a good spark there though....i also tried switching the carbs and same results..i'll try it on the water tomorow and see...again the original problem was it would start up no problem..run great for a while then all of the sudden just die...i'd wait 30 seconds it would start right up and be fine at idle speeds as if going through no wake areas...but once its running at higher rpms..like cruising speeds..it runs great then with no warning die..i tried running it on portable tanks with the same results..i've changed the plugs fuel filter..and now rebuilt the carbs...any other ideas!!

 

[Joe Reeves]

Re: messed up my carb!!!help

What is the compression on all of the cylinders on that engine? The cylinders are numbered as follows.... standing in back of the engine facing the spark plugs.

2.....1

4.....3

 

[rob711]

Re: messed up my carb!!!help

120 on all 4