1989 johnson gt150 tj150sclem - how do i set the timing ??

[KKNOPP26]

hey all, just finishing up a rebuilt on an 89 johnson motor and tracker bass boat. i have checked, repaired or replaced every component on this motor and am just finishing up a broken woodruff key. my question is. A) how do i ckeck the timing of this motor B) ho can i set the timing at spec, or something close to specs

i looked through the forum and found this(below, highlighted gray), for which im not entirely understanding and was hoping i could get an another explanation on / ask some questions!

Thanks for your time!

NOTE: If your engine has the "Fast Start" feature", you must disconnect/eliminate that feature in order to use the following method. The "Fast Start" automatically advances the spark electronically when the engine first starts, dropping it to normal when the engine reaches a certain temperature.

The full spark advance can be adjusted without have the engine running at near full throttle 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 a spark tester and have the gap set to 7/16". 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.

 

[emdsapmgr]

Since the ignition systems on these crossflows internally increases (timing creep) the timing the faster the engine goes, the factory requires that the timing be set at 5000 rpm's. That's assuming you have all the factory tools to set it. Which none of us have. I've seen an OMC tech set the timing at 5000 rpm's by backing the boat partially down the launch ramp. Once the water pickup is buried underwater, he ran it up to 5000. Sprayed water for 100', but got the timing set. Some folks are not comfortable with this. A good alternative is the timing procedure at the top of the first post of this forum. It's hidden within the first thread, called "top secret files." It involves running the engine at idle rpm, but compensating by 4 degrees, as you've noted in your post. It will get your timing close enough.

 

[KKNOPP26]

im not opposed to either method, i can always get help to do the ramp style adjustment but if they provide similar utility i think im gunna stick with the non rpm intense procedure, tho im not understanding the step of:

Rig a spark tester and have the gap set to 7/16". 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

I have a spark tester, so set that to 7/16, inline on cylinder one
crank the engine

from here, what am i looking for? and too set timing it is the rotary dial on the airbox, top one. i believe rolling towards the motor reduces time. is one complete revolution of this dial one degree?

 

[Bosunsmate]

from here, what am i looking for? and too set timing it is the rotary dial on the airbox, top one. i believe rolling towards the motor reduces time. is one complete revolution of this dial one degree?

Im not sure on that motor, would need to see a photo of the flywheel and this dial.
On most ive done the flywheel has the timing markings on it and theres a pointer on the side of the engine, all i do is find out what the engine requires at max advance (say its 27deg) well then you take off 4deg to make it 23 degs. You then hook up your timing light to no1 cylinder and while cranking the engine use the adjusting stop on maximum advance until the flashing light lands on 23. Thats all there is too it when ive done it, important to get right otherwise you risk burning up the engine or beig too underpowered.

I also check that tdc matches with the flywheel when i do this.

 

[KKNOPP26]

ill find the correct value for timing. so im adjusting the rubber stop to change timing essentially ? i will psot pictures when i get home from work, thank u!

 

[Bosunsmate]

ill find the correct value for timing. so im adjusting the rubber stop to change timing essentially ? i will psot pictures when i get home from work, thank u!

No worries, yes thats it, the stop adjusts how far forward the timing can go, if you in an imaginary world removed the stop then when you pressed the control lever forward the timing would go so far advanced that the engine would burn up from the too far ahead pre advanced ignition