88 evinrude 48 spl- carb spits fuel out top orifice

[Dan OVadka]

just purchased 10 days ago. Engine set 2 years. Started right up but misses every 3 to 5 secs. I purchased a manual, put cab kits in, changed plugs and plug wires, checked compression and spark.(120 top and bottom. Top jet spits fuel out. I am new. Am complete amature. any help greatly appreciated- I am stumped.

 

[Goodoleboy]

Re: 88 evinrude 48 spl- carb spits fuel out top orifice

Welcome to the forum Pugsley!<br /><br />Spiting back thru the carb throat means faulty reeds.<br /><br />They are behind intake manifold that carbs bolt onto. Some times they can be cleaned up by doing a decarb procdure on engine.<br /><br />you can read up on how to do that in FAQ'S at top of this page. <br />Hint...Theirs some really good words in FAQ'S. Read sleepping engine.<br /><br />You should also change the empeller in water pump.<br /><br />Good luck!

 

[R.Johnson]

Re: 88 evinrude 48 spl- carb spits fuel out top orifice

You most likely have a lean fire spit-back from a clogged carb, The problem being the low speed circuit. Clean the carb's, plus a rebuild kit. Faulty reed's are very unlikely. I have a hard time understanding why the reed valves' in these engines are so mis-understood. I would like to know where the light leak test came from. These carbs' are simple to rebuild, but pay attention to the slow speed passages'. I have replaced very few faulty reeds' in my time.

 

[Dan OVadka]

Re: 88 evinrude 48 spl- carb spits fuel out top orifice

thanks for the replies! If this helps, I can see the fuel spit out the low speed jet, and when it spits the engine misses. This is a really simple carb and I did clean and put in a kit. I must be missing something. I'll clean it again.

 

[Goodoleboy]

Re: 88 evinrude 48 spl- carb spits fuel out top orifice

RJ.....I took it to mean spiting or spraying fuel back thru carb. Not as cough back thru carb.<br /><br /> Am I wrong to say that spraying fuel back is caused by reeds not sealing.<br /><br />Ill stop saying that to people if Iam wrong.<br /><br />I thought I had read someplace that this was symption of poor sealing reeeds.<br /><br />Thanks!

 

[R.Johnson]

Re: 88 evinrude 48 spl- carb spits fuel out top orifice

I have seen a lean spit-back come back through the carb many times. I don't know as though I have ever cured a a rough running engine with a reed replacement, unless the reed was broken. I broken reed will blow back fuel through the carb at any speed, and that engine will fall off dramatically. Any two stroke will blow a certain amount of fuel back through the carb throat. Keep in mind! those parts' are moving along quite merrily. You can improve an engine with with a reed change, such as the Boyesen, but you can't cure an underlying problem, such as a clogged carb. In fact! that would destroy a Boyesen reed. In my opinion, a reed that is not bent, " unlikely" or broken is OK.

 

[Goodoleboy]

Re: 88 evinrude 48 spl- carb spits fuel out top orifice

RJ....Thanks for your thoughts on what reeds do and dont do.<br /><br />Sometimes its difficult to make out what a person is sayin about spray back, spit back and cough back.<br /><br />Reeds are seldom a problem. I do agree about that.<br /><br />Thanks!

 

[Basscat 1]

Re: 88 evinrude 48 spl- carb spits fuel out top orifice

Looking at my OMC manual, page 2-8, says a broken reed will cause a backfire. A backfire has to come through the carb, thus emiting a spit-back through the carb. Its only logical, if a reed valve was broken or missing, as the crankcase became pressurized from the piston on its downward stroke, that the pressure will go out the path of least resistance which is right by the broken reed and out the carb, thus causing a backfire or spitback.<br />Usually when a reed breaks it causes substantial damage to the engine, unless you are lucky like the guy I read on here who said his reed was lodged in the intake port and didnt get into the piston. Some people do win the lottery, so I guess it is possible.<br />The light test is something a buddy of mine who has been working on outboards for 20 plus years showed me. You dont have to do it, but I do.<br /><br />I would check the reeds as suggested by Goodoleboy. Possibly it is just not sealing around the reed block.

 

[Joe Reeves]

Re: 88 evinrude 48 spl- carb spits fuel out top orifice

Pugsley..... As per a quote in your second entry above, "If this helps, I can see the fuel spit out the low speed jet, and when it spits the engine misses."<br /><br />That indicates that you've overlooked something in the carburetor(s), and that the carb is running lean. Besides soaking the carb when cleaning/rebuilding, it's a good idea to also manually clean them out with a solid piece of wire.<br /><br />Keep in mind that the top foremost jet, the one that's visible when viewing the front of the carb, is a air bleed jet which meter air, not fuel..... the bigger the hole, the leaner the mixture is.<br /><br />On that model, you may have one of three carburetors. One that has a "fuel" metering jet in back of a seal screw on the starboard top side of the carburetor. Or one that has an adjustable needle valve in that same location. Or one that does not have either in that location.<br /><br />At any rate, do this.... with the engine running, stick a finger or two carefully into the throat of the spitting carburetor, acting as a manual choke of sorts which will richen the mixture slightly. Carefully so that you do not actually flood that cylinder.<br /><br />If this causes the problem to cease, then you can be assured that carburetor is running lean.<br /><br />If a reed plate (leaf valve) was stuck open, broken, whever, fuel would be blowing out the carburetor throat with every downstroke of the piston.

 

[Dan OVadka]

Re: 88 evinrude 48 spl- carb spits fuel out top orifice

I want to thank all of you that responded. I pulled the carbs back off this morning and went back through both.At the same time I pulled the reed valves out and cleaned and inspected them. They appear to be fine. This is the carb with no adjustment.Restricting the air flow with my fingers smooths the idle out. Placing my hand halfway over both makes it even smoother.I assume that I either need to replace the carbs or re-jet them. Is there a replacement carb that is adjustable that will work for me? I can not find any obstructions in these.

 

[Joe Reeves]

Re: 88 evinrude 48 spl- carb spits fuel out top orifice

Look closely at the top front air bleed jet. There will be a number imprinted upon it, probably #36 which indicates the hole is .036 . The OMC/Bombardier part number of that jet is 323703.<br /><br />It's possible that you may need to change that jet to a smaller size but that's the only part you'll need to replace..... BUT before you do that, check the following.<br /><br />In the center of the extreme lower portion of the top body, the part that extends down to the bottom of the float chamber, look inside of the large brass tube (high speed venturi).<br /><br />There you will see a much smaller tube which is not centered (it supposed to be that way, do not attempt to center it). That small tube is actually the fuel passageway for the slow speed. As you can see, the entrance hole is quite small and that tube can be resrticted quite easily, usually due to sitting without running.<br /><br />Besides soaking the carburetor in carb cleaner, I would advise that you locate a strong fine steel wire that will enter that small hole in order to clean out the inner portion of it.<br /><br />The fine steel wire I use..... I bend about 1/8" of the tip at about a 45° angle so that when I'm pushing/pulling it thru the tube, it is also scraping the inside wall of the tube.<br /><br />This has cured many a lean carburetor condition for me.... hope it works for you.<br /><br />NOTE...... DO NOT use a wire that might break. Should a piece of wire break inside that tube, that would really be a mess! If you can't locate a proper wire, email me your address and I'll send you a few. ReevesJ32@aol.com<br /><br />The above assumes that you do have new or very good gaskets in back of the carburetor, on the body halves, and the small round one on the center venturi to avoid air leaks. They must be in excellent condition.<br /><br />Another condition that may exist is that the carburetors are not synchronized properly...... <br /><br />Loosen the screw that retains the carb roller and back the carb roller away from the cam that it rides against. Now, loosen the screw(s) that retain the throttle linkage..... the throttle butterflies (all) should now be shut. Tighten the retaining screws. This should have the throttle butterflies set so that they open and close at the same time.<br /><br />Back to the roller..... adjust the roller so that the cam makes contact with it when the scribe mark on the cam is dead center with the roller. tighten the roller set screw. That should do it.<br /><br />NOTE.... That carb roller should be approximately 5/16" in diameter (roughly). If it is about 3/16" (again roughly) in diameter, the outer sleeve has broken and flaked away, in which case, purchase a new one.

 

[Solittle]

Re: 88 evinrude 48 spl- carb spits fuel out top orifice

One can add little to Joe's advice - - You might include in the cleaning process liberal use of high prissure compressed air - - not from a rattle can - - paying particular attention to the small passages.

 

[Joe Reeves]

Re: 88 evinrude 48 spl- carb spits fuel out top orifice

SoLittle.... You betcha! An air compressor is actually a must have item. I appreciate you bringing that point up.

 

[fishnfiend]

Re: 88 evinrude 48 spl- carb spits fuel out top orifice

Can't offer any better advice than above, but a welding tip cleaner has a number of tiny wires that could be helpful. Also, the OMC manual suggests a syringe filled with isopropyl alcohol. Without a needle, the syringe fits perfectly on the bottom of the idle pickup tube. Give that sucker a push and watch the alcohol squirt out the top of the carb! The other advantage of using alcohol is that you can see when it's flowing clearly, as opposed to air which you can't see.