1977 115 hp top seal question

[Charlie5653]

If I replace to top seal on the crank should I pull the bolts and also replace the large O-ring? ( Is that possible?) The engine set for 12 yrs and I know the lower unit seals are shot so I thought these most likely are also. Possibly causing my lean coughing condition at idle. All other possibilities for the lean condition I believe have been addressed.

If that dont do it I guess I'll pull the block and check the lower crank seal as my last option.

Thanks for any help, Charlie

 

[Joe Reeves]

I understand your line of thought... BUT... there's an old saying.... "If It Ain't Broke, Don't Fix It!"

In my 30 years+ of being in the trade, I've never seen one of those "O" Rings leak.... always replaced them if the unit had to be dismantled for some other reason... BUT... to replace them on a preventive basis... never. Most of the time, endeavors of that kind just create problems. Unless a leak is obvious, leave it be.

Sitting for 12 years.... That lean condition is caused by fouled carburetors, a slightly clogged idle jet, a air leak somewhere in the carburetor or intake manifold area.

 

[Charlie5653]

Joe, Thanks so so much for your time to help me. I've been trying so hard for about 5 weeks to get idle. I've had the carbs off 4 times and the intake off 1 time . I used grease on the gaskets to seal when re installed. I'll take them all off again and this time I'll use permatex aviation

 

[F_R]

Actually, intake gaskets should be installed dry. If you feel you must, grease is better than gasket sealer.

Are you positive you have the link & sync correct?

 

[Joe Reeves]

Joe, Thanks so so much for your time to help me. I've been trying so hard for about 5 weeks to get idle. I've had the carbs off 4 times and the intake off 1 time . I used grease on the gaskets to seal when re installed. I'll take them all off again and this time I'll use permatex aviation

As "F_R" states... DO NOT use any kind of sealer on those carburetors or for that matter, any portion of the fuel system as it will most certainly work its way into the fuel passageways and do more harm than good. Do this before tearing into the carburetors again instead.........

With the engine running, the idle problem, coughing, spitting back, etc, and the carburetor face plate removed which give you full access to the carburetor throats..... one by one, stick two fingers directly into the carburetor throat acting as a manual choke of sorts. When the engine smooths out a bit and the problem ceases, at least for a moment or two... you've found the offending carburetor. Get back to us with the results of that finger test and we'll go from there.

 

[Charlie5653]

Oh my good lord !!! Thanks guys.... Will do the carb throat test today. and will respond here.

THANKS AGAIN !! Charlie

 

[Charlie5653]

Also regarding link/sync I will give another good hard look to ensure butterflies are fully Closed in unison

 

[F_R]

Are all four idle orifices still the same, #29? If not, is there possibility they have been removed and mixed up?

 

[Charlie5653]

Well, Butterflies are ssurly closed. putting my fingers in each throat (one at a time) does not phase the engine, it continues to idle rough with zero rpm change. Also I can close down the manual choke to prob 98% closed as this seems to drop the rpm 100 but the miss never goes away. full choke will kill it every time.
The engine will start everytime with so much ease (half a crank every time)

Im so stumped, have been for weeks !!!!

 

[Charlie5653]

I didnt take out the idle orifices but when cleaning the carbs I did ensure the passageways were clear. I put the screw back on the idle orifice (new washers) and sprayed carb cleaner from the hole in the bottom of carb to ensure fuel would pass through the orifice and out the 4 or 5 tiny tiny holes in the carb for idle. I'm confident there is no blockage there

Great thought and advice, Thanks so much!!

 

[Charlie5653]

You guys got me thinking to do another style finger test. At Idle if I put my finger over the 4 little idle holes in the carb throat for each cylinder the rpm's drop a bit, when I remove my finger rpm's come back up ( its really a slight difference but I hear it) but nothing done there removes the miss. its simply a really rough idle

 

[Joe Reeves]

Whoa!! Four little idle holes in the carburetor throats?,,,,,, What four little idle holes?

Are you speaking of idle air jets being installed in the inside top portion of the carburetor throats?

What's the model number of that engine?... Do the carburetors actually have choke butterflies?

 

[Charlie5653]

Also maybe worth noting to you pro's , the lean sneeze seems to be gone however the idle is still rough ( jumps around in a range of 300 or so rpm's. Engine is on boat in a test tank. Sometimes when I start it the rpm's are around 500 and other times 800 but regardless of what range it will still bounce around 800 to 1000 or maybe next time 450 to 750.

I hope i'm not getting on your nerves with all this info, just trying to be informative to you guys

 

[Charlie5653]

model 115ETL77S serial J4776065 Joe, theres 4 or maybe 5 (memory) tiny tiny holes in the bottom of the throat for each cylinder, when the butterfly is fully closed there is a small notch in the bottom of the butterfly that rest over these tiny holes. I assumed the notch was for "air" to draw up fuel from these tiny holes in the throat. I replaced all 4 welch plugs as they are right underneath the tiny holes?

 

[Joe Reeves]

I can't visualize how you could possibly get your finger past the choke butterfly and place it over the idle fuel inlet passageway with the throttle butterfly closed and in the way. However, the rpm change you're speaking of now goes far past a lean setting problem... it indicates a missing problem.

Spark plugs should be Champion QL77JC4 plugs gaped at either .030 (long life) or .040 (strong spark)

Remove all spark plugs and do a compression test... what are the psi readings of "all" individual cylinders.

Plugs still removed... Test the spark which should jump a 7/16" air gap with a strong blue lightning like flame... a real SNAP! Does it?

 

[racerone]

Put a big fan beside your test tank to blow away the exhaust.

 

[F_R]

Maybe I'm not understanding, or you are doing something I've never tried. How the heck do you get your finger over those little holes? Long, skinny finger, or is it really that wide-open?

 

[Charlie5653]

I've not had the flywheel off as all electrical checked out fine. would it be worth my time to pull it and inspect the seal? I dont even know if the crank chamber can draw air from that seal if its bad? just a reoccurring thought... the motor just sounds lean to me

 

[Joe Reeves]

I've not had the flywheel off as all electrical checked out fine. would it be worth my time to pull it and inspect the seal? I dont even know if the crank chamber can draw air from that seal if its bad? just a reoccurring thought... the motor just sounds lean to me

Am I correct in assuming that you don't want to bother checking the compression and spark Charlie?

 

[Charlie5653]

Plugs L77JC4 / I didnt get the QL's because the manual said L77, I have wondered about that.....

Idles best at .030 for some reason -- I've tried 030 035 040

#1 228 lb / 2 122 lb / 3 124 / 4 120

spark is good snap at 7/16