90' 85hp tuning suggestions? Procedure help

[Carusoracer]

New to outboard motors and looking for help

90' CV85ETLD. Engine new to me. Previous owner rebuilt carbs and stated that he tuned it last time it ran 6-7 months ago.
Using outboard motor flushers: Started the engine and it idles nicely until above 2000 rpm approx starts to breakup and sound lean.

I do not want to take it out on the water without knowing Its right or at least how I can make adjustments? I have a service manual but not an owners manual.
What's the procedure to adjust the carbs? Or should this done in the water and if so how?

I've road tuned my triple side draft Mikuni carbs on a car a for a few years. So I'd prefer to learn myself if possible.

[rodbolt17]

number ONE thangy here.
FUGGIT ANYTHING AND EVERYTHING YOU THOUGHT YOU KNEW ABOUT CARS>

trust me on this.
if you were tuning a Coventry climax with twin SU carbs or a V12 jag with SU carbs ,,, maybe.

but your not.

your dealing with the most basic dirt simple non oil injected two stroke ever built.

other than syncing the MECHANICAL links to insure all three shutters move at the same time,,, that's all there is to syncing those carbs.

you basically have 3 engines that share a common crankshaft.

dirt simple carbs.
dirt simple ADI/CDI ign system .

the pulse fuel pump can take out a cylinder.

[Carusoracer]

number ONE thangy here.
FUGGIT ANYTHING AND EVERYTHING YOU THOUGHT YOU KNEW ABOUT CARS>

trust me on this.
if you were tuning a Coventry climax with twin SU carbs or a V12 jag with SU carbs ,,, maybe.

but your not.

your dealing with the most basic dirt simple non oil injected two stroke ever built.

other than syncing the MECHANICAL links to insure all three shutters move at the same time,,, that's all there is to syncing those carbs.

you basically have 3 engines that share a common crankshaft.

dirt simple carbs.
dirt simple ADI/CDI ign system .

the pulse fuel pump can take out a cylinder.

Ok that's good to know about that the throttle plates are an easy synch.

So, how do I test the engine without going out on the water? What's causing mid range breakup? Should I be adjusting the pilot screw to richer the mixture? Rather one on the lower case unit or under the cowling?

[rodbolt17]

dude
ya simply gotta QUIT.


its aint a bike.
it aint a car.
its not even an aeroplane.

it IS a marine outboard, very simple very high performance,

reving the engine on a two stroke out board with no load is a teat on a boar hog at best and simply stupid at worst.

to perform correctly that motor has to have EX back pressure AND a prop shaft load.
yes its that simple.

revving on a flusher will indicate NOTHING at all.

clean the carbs,about an hour, test/replace the fuel pump, 15 min.
test the ign system and compression at cranking, 10 min.
then other than some very rare CDI issues, your ****en.
not in that order

I typically test spark and compression then fix the fuel system.

remember on the ign system, you have ign PRODUCING and ing CON*****ING circuits.

[Carusoracer]

Well back off the water from a very frustrating first sea trial. Engine would run at idle fine start fine and the go into reverse with power. After that all down hill. Motor would cut out every time I tried to put into forward and then no power to start?
Try again in idle no power to start...tilt motor works fine up and down. Somehow it will start again then same thing, fine in idle, dies out trying to go into forward gear. Then no power to start.

Paddle back to the dock. Take it over to the boat yard, put it on the flushers, engine starts fine multiple times, and runs in forward and reverse. It still breaks up over 3500 rpm. And yes there is no load. I now have no confidence to go back out again without addressing the issues

The biggest issue I smell is that it is running very rich and smells of gas. A lot of gas. I have a separate oil injection unit feeding the motor. I also charged the battery just in case for 6 hrs with good readings before heading out.

Any help appreciated.

[rodbolt17]

and I am still telling you, with no load you can toss 2 plugs in the crick and it will still rev to about 3000 RPM.
revving with no load is a teat on a boar hog.
period.

test compression.
test spark.
fix the fuel system.
dirty carbs will do what your describing as will a blown fuel pump diaphragm.

[99yam40]

easy to test compression, spark, and timing , if all is in spec then chase the fuel problem.
There are no magic ways to tell what the problems are without testing.
But you can guess and throw parts at it until it runs properly if it ever does

[greasyshaft]

Replace the boat... problem solved