Video, why does my E35 behave like this?

[Vandkanten]

Fresh compression numbers is 110,110,120. Tested on cold and warm engine.
New plugs.
All 3 carbs is cleaned.
Running premix.

The engine can run on 1 cyl by disconnecting the other two cyls. I have testet, it can single cyl run on each of the 3 cyls.

I had the engine running for about 30 minutes and temperature never gets over 75d / 163f. But it is too hot for my hands.

I think the engine acts strange on the upper cyl/carb,

see https://youtu.be/MSSD5t8wRB0

I also took out the new plugs, see the picture. Left is upper cylinder. Is something wrong here?

 

[Rustywrench]

Well first off this motor has OIS (Optical Ignition System) & can be irritated by any spark plug but Q Champion spark plugs. The '98 model calls for QL86C plugs. NGK does not make a Q type plug. The top plug looks lean. At idle you might squirt a little fuel in that carb to see if the motor picks up a little. I would check that carb over for fuel flow. If the motor is running on it that doesn't mean it is getting enough fuel at higher speeds? If you have a a way take out the main jet & clean it along with the whole carb.

 

[Vandkanten]

Thanks Rustywrench for your input. I still have the old Champion QL86C plugs. Tried them in, with same result. Carb 1 is just not sucking enough air like the other two carbs. Anyway, I will order 3 new QL86C plugs.

Tried squirting fuel in the carbs, doesnt seem to do anything at all. (I have dual butterflies, one open, one closed)
I also tried squirting fuel in the upper cyl, and I got alot of smoke when starting, so it does fire.

I tried swapping two carbs, to see if the problem follows. It did not follow.
I have 3 extra carbs (not cleaned) for the engine. I swapped the upper carb and still same problem.

In all these scenarios, I also tried to run on only upper cyl just to be sure that it was working with spark etc.

I know that I should'nt run high RPM with no load but had to for testing.
At high RPM ~3000 RPM it is sucking air in, but again nothing compared to the middle and lower cylinder.
At high RPM the engine temp lowered alot.

It seems like the cylinder is sucking air/fuel from somewhere else since it doesnt take much from the upper carb.

Any ideas ?

 

[Bosunsmate]

Upper seal perhaps

 

[Vandkanten]

I have checked the diagrams.
Where is Upper seal located ?

 

[Bosunsmate]

top of the crankshaft, under flywheel

 

[Vandkanten]

Do you mean part #11 and/or #12 at https://www.marineengine .com/parts/johnson-evinrude-parts.php?year=1998&hp=35&model=E35KLECA&manufactu rer=Evinrude§ion=Crankshaft+%26amp%3B+Piston
(remove space just before .com)

I actually begins to believe that you may be right.
I guess that if that seal is worn or damaged, air may enter when the pistons makes a vacuum making it suck less from the carb. And it also makes sense that it is the upper cylinder have the problem, cause it is closest to the seal.
I will have to investigate this.

Can this foul a compression test? I have testet it serveral times and the 3 numbers is very close to eachother.

 

[kbait]

Compression psi on upper cylinder wouldn’t be affected by leaking upper crank seal. Pull flywheel and check seal area.. if leaky, it’s usually pretty oily around the seal. To confirm, squirt a bit of oil on the seal and turn the motor over (put in forward gear and spin prop forward w/foot.). It will alternately suck/blow past seal if it’s leaky..
Good luck!

 

[Bosunsmate]

Those a good ideas from kbait,
Sometimes its like its just an intuition and there will be no sign of failure but replacing it fixes the problem so even though it didnt look faulty it was the problem.
Since cylinder 2 is ok then your internal crank seals seem ok, they usually are.
The last thing would be a broken inlet reed but you normally get backfires and lots of spitting out the carb if that was the case.
Good thing those seals a cheap. If you have to split the crankcase on that model (hopefully not) be sure to do the lower one too.
Top ones on many models you can pull out with a pick and slide the new one down using the old one as a shunt.

 

[Vandkanten]

Thank you kbait, I will look into it very soon.

One thing I forgot to mention, is that when the engine runs, I hear a clicking sounds from the upper inlet (something like dic dic dic dic dic...). I guess that the same clicking also comes from lower and middle inlet but not as clearly as from the upper inlet.
I have checked the reed plates through the inlet hole and they seem intact.

 

[Vandkanten]

I testet the upper seal with oil while rotaing the engine, no suction or air bubles.

I investigated the reed plates and they looked fine from the outside.
Removedd the intake manifold and well, well, will you look at that!

The inside of the intake manifold is in a very bad condition, rusty. Lucky me, I had a replacement by hand.
I checked the inner pistons, looked good to me.

Assembled the engine and it fired fine. Got better suction of upper carb, I guess. Hoping that the rest is just carb adjustments.

 

[Bosunsmate]

put a dollar note over each carb, check they suck the same, if the top one blows it back you will need to inspect closer those reeds

 

[Bosunsmate]

ah just seem your update, wow very rusty, ive never seen that but im no long in the tooth shade tree mechanic

 

[Vandkanten]

Thank you Bosunsmate I will try the dollar trick tomorrow.

Funny, cause when I look at the engine, it looks like it were made yesterday. Really.
Only sign on worn were a few nipples that were rusty.

Guess I should take off the cylinder head and make an inspection.

 

[Bosunsmate]

yep it does suggest you may need to clean out the cooling channels in the head from rusty/oxidative build up

 

[Vandkanten]

It works perfect now, so I am closing this one down.
Removed the 3 carb link, and adjusted each carb one by one. Put link back on and adjusted the idle screw.
Had the engine on water today and now the engine runs like a dream.

Thanks for all your thoughts and helps.

 

[kbait]

Thanks for the follow-up!