Recent rebuild, no WOT????? (several pics)

[Theoutdoorsman]

I am in the middle of rebuilding my carbs again on my very recently rebuilt 1979 Evinrude 140. So far, I haven't been able to get her past 2000 rpms since the rebuild and I continue to hear this annoying cough at an idle. Compression is at 110 all the way around and even. The link and sync was fine. I had her idling at 4* BTDC as per the service manual and the WOT was set to 24* as per the Joe Reeves meathod. Also, I ensured I was getting good fire, via the spark test with my homemade spark tester, which looked good. (Dazzled my 7 yr old son BTW........LOL) The temperature is holding steady at about 130*. Too, I have purchased a seperate 6 gallon fuel cell to aide in the troubleshooting process. I did noticed, however, that the cowling under the lower carb was covered with fuel and figured I had a float adjusted incorrectly. So I've pulled them off again because I know all the fuel line is brand new with the exception of the "T". Core plugs have been removed and carbs have soaked for about 8 hrs now. So far as I can tell, everthing appears to be very very clean and looked just as clean prior to rebuilding them this time. I even made a visiual inspection of the passages using a flashlight shined down the throat of the carbs and visually inspecting the low/high speed orifice passages, with the orifice plugs removed of course, as well as all other passages. I can see good light through every passage. Am i missing something here? Or is it possible that I simply mis-adjusted the floats? Man I need some serious help here. I really want to get this thing up on plane!!!! Anyone have any advice?............. :'(

 

[Joe Reeves]

Re: Recent rebuild, no WOT?????

Re: Recent rebuild, no WOT?????

(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.

I assume that while those high speed jets were removed that you manually cleaned them rather than assume they were soaked clean? If not, do so.

Check that the timer base under the flywheel moves smoothly from its idle position clear up to its full spark advance position (engine not running).

Spark plugs should be Champion QL77JC4 plugs, gapped at .040 .

What is the compression on each individual cylinder, and does the spark (with the plugs removed) actually jump a 7/16" gap on all cylinders at cranking speed?

When the engine is "coughing at idle", one carburetor at a time, stick two fingers into the carburetor thoat (acting as a manual choke) to riched the mixture, but not enough to flood a cylinder. When you reach the carburetor that eliminates that cough you've found the offending carburetor/cylinder.

Let us know what you find.

 

[Theoutdoorsman]

Re: Recent rebuild, no WOT?????

Re: Recent rebuild, no WOT?????

Joe Reeves.......... Yes I removed the high speed orifices and made a visual inspection of all 4. I can see good light on all and they appear to be spotless. The timer base is not sticky either. It moves freely and goes all the way to the stop. I'm jumping a 7/16 gap, on the spark on all 4 cylinders, via looking at my spark tester while cranking the engine and verifying my WOT timing as per your meathod @ 24* while cranking. The only difference I can see, are the plugs I'm using. I have installed 2 sets of brand new UL77V Champion Permagap Plugs. These are as per my service manuals recommendation. All appeared wet when removed and inspected. I will try the two fingers in the carb throats when I get the carbs back on. If the problem persists. As stated earlier, compression is 110 all the way around and even. Could the crank case halves not have sealed properly? What negative effects could that have if they didn't seal? I understand the fuel pump, which I plan to rebuild before attempting this again, opperates from the vaccum within the crankcase. Is it possible that this could be the problem. Again, what symptoms would I be seeing IF this were the case? Thanks a bunch for your help on this. It is much appreciated. I'm am at my wits end on this.................... :'( ........... I've included some photo's of the carbs and jets, both high and low speed, to let you see first hand that the passages are clean. Both carbs look identically clean. Thanks.............. ALAN

 

[Theoutdoorsman]

Re: Recent rebuild, no WOT????? (several pics)

This photo is of my most recent link and sync. Throttle valves and choke valves have been synced according to my manual. If anyone see's anything that they feel might be wrong, please let me know................. ALAN

 

[Dhadley]

Re: Recent rebuild, no WOT????? (several pics)

The rod in the cam follower looks screwed out a little too much but won't cause what you're describing. Usually the threaded part of the rod is about 1/2 way. That's why the screw in the plate to adjust the roller is so far forward. No big deal.

Don't worry about a specific timing at idle. Just adjust it so it idles at 700 or so at idle, in gear, in the water. At idle the butterflys should both be closed.

Now, a really dumb question -- the idle pockets look great, as do the carbs. But on reassembly you do put the core plugs in, right? (Those little aluminum plugs that look like freeze plugs)

 

[Theoutdoorsman]

Re: Recent rebuild, no WOT????? (several pics)

Dhadley.......... It's great to hear from you again sir. I certainly hope things are going well on your end.

The core plugs have always been installed. I cannot, for the life of me figure out why I have this cough at an idle and no WOT. Everything appears to be in absolutely great condition. The timing was right at 4 1/2* and idling at 800 rpms on the water and in gear. I did have one of the floats set a bit too high, I think, on the free end (non-hinged side). It was on the bottom carb. I'm just not certain this would cause what I'm experiencing. Because this same type cough is what lead me to inspect for broken rings, I re-checked the compression to assure myself this wasn't dajavu, and all is well. Compression looks good. I have a new fuel pump rebuild kit on the way here now, just because it's the only part of the fuel delivery that isn't brand new, rebuilt, or been cleaned. Do you have any idea what else might cause this cough? Reeds? Crank case not sealed well? Thanks a bunch for your interest.................. ALAN

 

[R.Johnson]

Re: Recent rebuild, no WOT????? (several pics)

The picture show's the core plug's un-installed. That would certainly give you a problem.

 

[Dhadley]

Re: Recent rebuild, no WOT????? (several pics)

Ok, you do have them in and you flatten them with a punch, right? Then seal them, right?

 

[emdsapmgr]

Re: Recent rebuild, no WOT????? (several pics)

Any chance the floats are in upside down?

 

[Theoutdoorsman]

Re: Recent rebuild, no WOT????? (several pics)

R. Johnson.......... I left the core plugs out to show everyone that the passages were clean. They have since been re-installed (new ones of course).


Dhadley......... .... I installed the core plugs using the end of a socket extension. No sealant was used because I had heard reports it isn't necessary unless the core plugs leak. In this case, I am told, you can tap them a time or two to make sure they are seated. Is there a way to test this and see if, in fact, they are leaking or not leaking?


emdsapmgr.......... The floats have been re-installed correctly, or at least I hope they are. I will post a pic of them installed to be certain.

 

[mikesea]

Re: Recent rebuild, no WOT????? (several pics)

Might be the fuel pump .You might be getting gas into the vaccuum,and not enough pressur at high speed.Have you tried squeezing the ball while trying to get full throttle,to help the fuel pump if its weak..Also,any chance of your choke i,f its the electric type the red switch could be by passing extra fuel into the engine,but that usually has no effect on high speed..Usually the crankcase cover will fart to the outside if its having a seating problem.Do you see fuel being thrown out of the carb. When this happens ,it often means reed problems.

 

[mikesea]

Re: Recent rebuild, no WOT????? (several pics)

One other thing I thought of.Assuming your plug wires are correct,but are the primary wires to the coils right.You may have a set of wires backwards.Some years have plug on wires for the primary (small)coil wires,some go into the amphenol connector,the coils without the plug on primaries could also accidently switched to the wrong cylinder.Ex. coil 1 on cyl. 2 ,if you suspect it just flip flop the spark plug wire to confirm.I'll bet it something simple

 

[Theoutdoorsman]

Re: Recent rebuild, no WOT????? (several pics)

mikesea............ I have the plug in type coil connectors. I have not noticed fuel spitting out of the front of the carbs, but I will take a closer look when I get these carbs back on. I have tried squeezing the ball and nothing happens. When I choke it, it stalls out. I have noticed though, that the system is hard to initially prime and I see no evidence of leakage. However, I have purchased a 6 gallon fuel cell for testing puposes to aide in isolating the source(s). And, once the system is primed, if I squeeze the ball and hold steady pressure on it afterward, the fuel will track backwards to the fuel cell and loose the prime. The arrow, or fuel flow indicator on the ball, is definitly facing the correct direction, towards the carbs. This is what leads me to believe it might be the fuel pump. I'll rebuild it before my next attemp at this if for no other reason than to rule that out too. Also, if the coil wires were switched, wouldn't the engine idle extreemly rough? It purrs like a kitten at about 1200-1400 rpm and the cough completely disappears. This cough is only present at idle speed. Does anyone know a meathod of testing for leaky core plugs? The carbs are ready for installation again, but I'd check them first if anyone knows a way to do so.

 

[i386]

Re: Recent rebuild, no WOT????? (several pics)

I had a similar problem on my old Chrysler last Saturday. Was hard to prime, bulb wouldn't stay hard and in my case was dang near impossible to start. Turns out the fuel line going to the input side of the fuel pump was not tightly sealed. I trimmed a little old hose off the end and re-clamped. Problem solved.

Could be you have a similar problem.

 

[Dhadley]

Re: Recent rebuild, no WOT????? (several pics)

OK, we'll assume the core plugs are seated and sealed.

When it coughs at idle is it sneezing out the carbs or coughing out the exhaust?

 

[Theoutdoorsman]

Re: Recent rebuild, no WOT????? (several pics)

Coughing out the exhaust............... here's the completed rebuild of the carbs, with the exception of the bowls of course.

 

[Dhadley]

Re: Recent rebuild, no WOT????? (several pics)

The pics didn't come thru for me but it could be this old 1902 computer.

Anyway, if it coughing out the exhaust, that's an ignition issue. Lets look at the easiest thing first and hope that's it.

Follow the orange wires from the pack to the coils. Make sure they're on correctly. The orange wire to the top coil on each side should have a blue tracer, the bottom one should have a green stripe. There may be some variations of tracer (stripe) colors but we're looking to make sure the firing order is correct.

The wires should be in a plug. Make sure the coils didn't get accidently mounted wrong. It happens all the time.

 

[reeldutch]

Re: Recent rebuild, no WOT????? (several pics)

check for fuel presure between the fuel pump and the carbs.
at idle it should be 2.5 psi.

if that checks out fine and your remote fueltank and primer bulp and all is brand new asumming its all ok, i would check the crankcase seals, head gasket etc.

when you rebuild it did you check the heads if they where flat?
did you check the crankcase seals or replace any?
did you face the seals with the gap up?
i have a feeling it might be leaking inbetween 2 crankcases.
that might explain the cough and not reaching wot.
may be during crankcase instalation something happened.

but first check if the whole fuel system is working propper and your timing is ok.
also make shure the engine temp is good.


reeldutch

 

[Theoutdoorsman]

Re: Recent rebuild, no WOT????? (several pics)

Dhadley........... I think you have once again saved my rear end on this thing!!!!!!!! I have the coils reversed on the port side cylinders. Blue stripe to the #1 on the starboard side and blue stripe to #4 on the port side. I'll be dog gone. If this works, I most certainly want to buy you a case of brew!!!!!!

 

[Dhadley]

Re: Recent rebuild, no WOT????? (several pics)

I'm sure that'll fix it. If not 100% then it should be a lot closer. No ned to ask how I thought of that, I'm sure you can guess how.

BTW - the carb pics came out and look fine.