timing 115 hp johnson

i need to time a 115 HP johnson 1978 V4 engine.. i dont have a test tank all i can use are water muffs...w/gargen hose..( i live 40 miles to the closest lake )..this engine is an older model.. i overhauled it this past winter..have had it running but its runs rough and wont idle at load speed...will run fine at full throttle...thanks for some pointers...

As long as you / someone did not move the timing stop screw ( the one with the rubber bumper ) the timing will be right on.--------It is fixed at the factory and should never need adjusting !-----------You can however empty the carburetors / advance timing to that stop / turn ignition on / crank the motor over with a jumper to the solenoid and check that timing.------------Do not crank for long periods as the starter can not tolerate that.

(Timing At Cranking Speed 4°)
(J. Reeves)
The full spark advance can be adjusted at cranking speed,"without" have the engine running as follows.

To set the timing on that engine, have the s/plugs out, and have the throttle at full, set that timer base under the flywheel tight against the rubber stop on the end of the full spark timer advance stop screw (wire it against that stop if necessary).

Rig up a spark tester on the #1 cylinder plug wire. Hook up the timing light to the #1 plug wire. Crank the engine over and set the spark advance to 4° less than what the engine calls for.

It's a good idea to ground the other plug wires to avoid sparks that could ignite fuel that may shoot out of the plug holes. I've personally never grounded them out and have never encountered a problem (fire) but it could happen.

I don't know the full spark advance setting your engine calls for, but to pick a figure, say your engine calls for 28°, set the timing at 24°. The reasoning for the 4° difference is that when the engine is actually running, due to the nature of the solid state ignition componets, the engine gains the extra 4°.

If you set the engine to its true setting at cranking speed, when running it will advance beyond its limit by 4° which will set up pre-ignition causing guaranteed piston damage! You don't want that to take place.

No need to be concerned about the idle timing as that will take care of itself. The main concern is the full advance setting.

Be sure to use your own engines spark advance settings, not the one I picked out of the air here in my notes.
Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1

As Joe says, but I would ground the plug wires. Some solid state parts don't like not having a place for the power to go, and tend to self destruct. Better to be safe, and not have to spend more money. Just my 2 cents.