I'm very concerned, I need some knowledge!

[wlbolerdo]

I'm not sure what "coughing and/or sneezing" is but my '92 70hp evinrude seems to be coughing or popping out the exhaust and spitting fuel out of the top carb at the same time! I pulled this carb and cleaned it, also re-adjusted the float level and blew into it to make sure it's working. I pulled all three plugs, The #1 or top one seems to be dry and the other two are wet. I re-built this power head back in July or August and don't want to do any damage. I looked at the reed valves and they looked ok but I believe that this top cylinder is not getting fuel. I would hope that someone could tell me what's going on here.
Thanks,
Wayne

 

[freddyray21]

Re: I'm very concerned, I need some knowledge!

need to check the top carb. could be in need or a rebuild. If it's not getting gas it's not getting oil so don't continue to run it like that.

 

[wlbolerdo]

Re: I'm very concerned, I need some knowledge!

I re-built the carbs including floats just before I re-built the power head. I'm so iritated and stumped! Someone has to have experienced this same problem. I really don't want to take it to the mechanic @ $90.00 an hour

 

[tashasdaddy]

Re: I'm very concerned, I need some knowledge!

i agree on the carb, they can be clean now, and 15 minutes pick up something. but, my first thought, is you did not torque the flywheel too specifications, and it has sheared the woodruff key, throwing the motor out of time.

 

[emdsapmgr]

Re: I'm very concerned, I need some knowledge!

My 92 spits fuel out of the top carb also. If you pull the carb off, it comes from a small hole in the intake manifold, where the carb bolts up. I believe it is a vent outlet for the internal crankcase line which lubes the upper bearing. Sounds odd, but it is normal. The drops of fuel/oil will either get sucked up in the carbs, or will drain into the airbox drain and will get consumed in the bottom cyl.

 

[ezeke]

Re: I'm very concerned, I need some knowledge!

Check the reeds anyway.

 

[James R]

Re: I'm very concerned, I need some knowledge!

Does a compression test tell you something. Can't recall but I think if the upper crank seal fails then you loose crank case pressure and fuel up into the top cylinder.
Tashasdaddy can you support that?

 

[CATransplant]

Re: I'm very concerned, I need some knowledge!

I'm with Tashasdaddy. Have you had the flywheel off....ever? If so, the key is probably sheared. That can cause a backfire through the exhaust and the carb.

If that's the case, be sure to torque the flywheel nut to the correct value after replacing the key. It's a very common problem when folks work on outboards.

Also, if the outboard is new to you, the previous owner may have had the flywheel off and not torqued it properly.

 

[iwombat]

Re: I'm very concerned, I need some knowledge!

Compression test tells you whether your rings are sealing and your head gasket is good after the piston closes up the ports.

 

[James R]

Re: I'm very concerned, I need some knowledge!

If the rings are not sealing then you have poor crank case pressure and poor fuel transfer.That was my reason for the compression test question.

 

[Benny1963]

Re: I'm very concerned, I need some knowledge!

had pop in m y crossflow after rebuild .
tryed the carbs over and over ,sonic soaked with air red rhino kits new floats
still popped , pulled carbs and looked real good in intake had piece of old .
gasket stuck in reeds ,then noticed one reed split .put in boysens and now it is purring

 

[Joe Reeves]

Re: I'm very concerned, I need some knowledge!

Wayne..... As suggested above a few times, take a compression reading of all cylinders. What are the readings?

With the spark plugs removed, the spark should jump a 7/16" gap with a strong blue lightning like flame... a real SNAP! Does it?

Spark plugs should be Champion QL77JC4 plugs, gapped at .030 . You might try the older recommended setting (gap) of .040 which might make a difference.

If the three above areas are as they should be, do the following.

With the engine running and the carburetor face plate removed, stick two fingers in the carburetor throats.

If the engine smooths out and a increase in rpms takes place, you've found the offending cylinder, and should this take place (no offense intended), you've overlooked something in that carburetor, OR a reed (leaf valve) is faulty, OR the reed plate gasket is faulty, OR leakage exists in the offending cylinder crankcase area (unlikely).

 

[wlbolerdo]

Re: I'm very concerned, I need some knowledge!

I'm sorry that I didn't check back sooner but I've already pulled the top carb off again to reclean it. The next thing I did is pulled out the top spark plug, turned the flywheel until the piston was all the way down and blew smoke into this cylinder ( I'm a smoker) and I had a faint amount of smoke coming through the reeds. Very faint but verified by my girlfriend. So at this point I'm going to replace the reeds for this cylinder.
Joe, I'll follow your instructions to the letter tomorrow before ordering reeds and will get the compression numbers as well. They were around 120psi for all three just after the re-build.
Wayne

 

[wlbolerdo]

Re: I'm very concerned, I need some knowledge!

Just an update from previous posts. I've replaced all reed valves in three cylinders, put everything back together and did a compression test. All three cylinders were at 130 psi, I'm pleased with that! It got late and very cold in the garage so I'll check the spark and fire her up tomorrow. I soaked the offending carb and put it back together with new jets. We'll see tomorrow.
Wayne

 

[wlbolerdo]

Re: I'm very concerned, I need some knowledge!

Here's another update.
Compression is 130psi at all 3 cylinders. Good blue spark jumping a 7/16 gap. Motor was still popping out the exhaust and spitting some fuel out the top carb! I got mad and turned the mixture screw counter-clockwise alittle bit and the motor smoothed out! Sounds pretty good now. Did the decarb with Seafoam on Wednesday and this morning found a small puddle of oil on the floor at the point where the prop and lower unit meet. Also found oil in the driveway where I was doing the decarb! Does this boat HATE me? Are the seals gone on my 70hp rude coincedently? Is this something else?
Wayne

 

[ezeke]

Re: I'm very concerned, I need some knowledge!

That oil discharge at the prop is perfectly normal and would be worse after a de-carbon treatment: http://forums.iboats.com/showthread.php?t=207285

 

[wlbolerdo]

Re: I'm very concerned, I need some knowledge!

So I've read the link and a baseball size puddle would be normal? That would be good for me but my luck has been aweful lately.

 

[Gary H NC]

Re: I'm very concerned, I need some knowledge!

After doing a decarb thats very normal. Black goo will run out for a couple days unless you put it in the water and run it good and hard.
Probably nothing to worry about.

 

[wlbolerdo]

Re: I'm very concerned, I need some knowledge!

I appreciate your input and I'll go with it. I'll be keeping an eye on it! That's what it seems to be, a black goo or thick oil.
Thanks again,
Wayne