92'evinrude 115 hp carb linkage & sync

[barry light]

Trying to adjust for correct timing per manual I have, but doesn't say what timing should be at idle ( On muffs in gear at about 1,000 rpm ). Should it be at "0" degrees ( TDC) with the two throttle plates in closed position? The manual says at the moment the throttle plates start to open the, timing should be 3-50 BTC. What is 3-50 ? Is it 3 1/2 degrees? Is this a misprint? ..... At WOT timing should be 28 degrees BTC.

 

[Haffiman]

Re: 92'evinrude 115 hp carb linkage & sync

Timing at idle is next to irrelevant.
What is mentioned is 'pick-up timing' when the mark on the cam aligns with the roller and the carbs starts to open, 3-5 BTC. If on a light boat with light load you may try 3, if more heavy you may have to increase to 5 to avoid a 'dead' spot just as the carbs starts to open.
Then set the idle when boat is launched, engine running in forward gear, boat free at around 800rpm.
To set the WOT timing, remove spark plugs and attach leads to a spark tester, alternative in the plugs but ground the plugs away from the plug holes.
Give full throttle, crank the engine and set max timing at 24. (Max - 4 degrees).
Hook up and do a test run.
DO NOT REV THE ENGINE FULL AT MUFFS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[barry light]

Re: 92'evinrude 115 hp carb linkage & sync

All good advice!
My manual did not mention your way of presetting timing for WOT, out of the water...Manual did advise not to run over 2,000 rpm on muffs, as you EMPHATICALLY STRESSED!!!!
Thank you very much, Mr. Haffiman!

 

[barry light]

Re: 92'evinrude 115 hp carb linkage & sync

Now for my real problem...I recently had local Evinrude dealer install a rebuilt powerhead for this motor. This 40 year Evinrude dealer does not have a test tank large enough for my 24' Grumman pontoon. I have picked up and brought back to dealer at least 5 times since the rebuild. Motor starts fine and idles fine. During breakin, with throttle all the way down it runs rough up to 2,500 rpm where it eventually smooths out, then rpm increases on its own up to 3,000 ( running roughly), then rpm increases to about 4,000 on its own( still running rough). This all takes place in a full 5-10 minutes. Dealer replaced coil to #2( did not change performance), dealer then changed power pack said no fire to coil #4 ..Had mechanic go with me to closest boat ramp, where motor still runs the same ( no change in performance), mechanic said seems to be in carbs....mechanic found trash in carbs and adjusted float drop to 1" as required ( he said they were at 5/8")... What gripes me is that during the rebuild, he cleaned out tank, installed new fuel line/primer bulb, new fuel pump ( VRO had been disabled and I was premixing) and supposedly rebuilt carbs as required...
Anyway, after carb work, engine still runs the same ( no change in performance)....HOWEVER, during this last test run in the lake, we ran for right at one hour after installing 6 gallons of gas, running an average of 2,500 to 3,000 rpm ( motor running rough pretty much all the time, same as before....BUT, all of a sudden the engine quickly ran up to over 5,000 rpm on its own, where I quickly pull back on throttle ( did not want to over rev during the breakin, engine sounded GREAT! ) and died. Squeezed primer bulb but could not get it firm. Fuel tank was empty. Put in fuel, and it still runs the same. I know this is long, and as you can see, from my original thread, I have been trying to check things out myself, between the times I keep taking it back to the dealer. You were so helpful with my original thread, is there something I could mention to the mechanic where dealer charges $94.50 per hour for repairs?

 

[Haffiman]

Re: 92'evinrude 115 hp carb linkage & sync

He does not need a test tank for the whole pontoon, just for the engine!!
Try to do the following:
Start with NEW plugs.
Check that plug cables are properly clamped to the cylinder head and well clear of the rear cover latches.
Use a 5 Gal portable tank to eliminate problems in boat fuel system.
Warm up engine and check both sides for even temp. Use your hands or better an IR gun.
Engine should run smooth at idle around 800 when i gear forward.
Do a test run.
Just slowly increase throttle until engine stops reacting, do not push/force too hard.
If problem, do a test run WITHOUT top engine cover.
Still same problem, take out the plugs and make picks as they are and post them.

 

[emdsapmgr]

Re: 92'evinrude 115 hp carb linkage & sync

Possible ignition problem. The engine may be running on only 3 cyls-till it revved up to 5000. Check for spark on all 4 plugwires when the engine is under load. Pull the cowling and us an inductive timing light for this test.

 

[Silvertip]

Re: 92'evinrude 115 hp carb linkage & sync

Check the setting of the lever on the primer solenoid. If it is in the MANUAL position the engine is sucking way more fuel than it should and woulld account for rough running at slow speeds.

 

[barry light]

Re: 92'evinrude 115 hp carb linkage & sync

Thanks for the responses from everyone. Dealer has found the problem. The intermediate carb orifice ( jet) was wrong size. Dealer is thinking this wrong size jet was installed before I brought the motor to him to install the rebuilt powerhead. Dealer thinks maybe that the engine lost performance with age ( 1992 model) and previous owner had someone to improve performance by changing jet size.....With the newly rebuilt powerhead, the engine is much tighter ( like a new engine would be) and the wrong orifice size was flooding the engine somewhat. Dealer installed the specified orifice and now engine runs perfect....My question after going thru this so much with the dealer, is that part of the procedure with installing a rebuilt powerhead is to rebuild the two carbs in this case.. I realize that rebuilding carbs includes new floats and gaskets, should it also include new orifices ( jets), or at the least check that the existing ones are correct size and not damaged?

 

[BonairII]

Re: 92'evinrude 115 hp carb linkage & sync

I realize that rebuilding carbs includes new floats and gaskets, should it also include new orifices ( jets), or at the least check that the existing ones are correct size and not damaged?

That's a tough one. He may have cleaned everything and not known that the jets were wrong size just by sight. Having the wrong size jets in a carb is probably a very very rare thing. Not many people replace their jets, let alone purposely put in a larger one I would imagine.