no power, J150tlcos, 1985

[diver_down]

long story short, end of last season i fried the stator; changed it (and the regulator), cleaned the carbs, drained the tank and put fresh gas, now the boat would not go faster than 1200-1300 rpm.
it starts right up, has spark in all cylinders, pumps water well, 80psi across the board compression, 6^ btdc spark at idle, the throttle advances as supposed to the carbs open but it just will not go. activating the choke changes nothing, if i push the throttle all the way it just dies instead of accelerating more.
on the muffs it will accelerate to 3000 if i raise the quick start (did not try more, don't want to screw it up).

any advice would be appreciated.

 

[Joe Reeves]

Re: no power, J150tlcos, 1985

If you had the primary wires removed from the coils for some reason, it's possible they aren't corrected properly. Top cyls = Orange/Blue, Center cyls = Orange, Bottom cyls = Orange/Green.

If the above is okay, your explanation would indicate carburetor problems, possibly something overlooked within them, UNLESS...... the engine was overheated which usually results in loose cylinder head bolts that would allow water to enter the cyls.

Might not be your problem source but it's worth a look.

 

[diver_down]

Re: no power, J150tlcos, 1985

you're the man joe, as usual; thank you.
I was going to do a link and sinc and recheck the carbs. back to it tomorrow morning. also, since you mentioned spark issues i guess i'll just go check it with a gap spark, see how good it is. I changed the flywheel as well (from 10 amp charging system to 30amp) so i might have to check that as well.
ohhhhh, back to square one.
thank you for ideas.

also, if somebody knows what the full throttle advance on this engine should be i would appreciate it - my shop manual says nothing on that, or i missed it somehow. the airbox says 29 btdc.

 

[Joe Reeves]

Re: no power, J150tlcos, 1985

If the engine's carburetor face plate says 29?, I'm not about to disagree with it.

(Timing At Cranking Speed 4?)
(J. Reeves)

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 temperture.

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.

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.