15HP 152BA Adjusting and Running

Hey! Looking to tune in my new to me Chrysler Outboard!
To get here see below and via a couple other posts:
Partially rebuilt carb along with many cleanings
Changed out fuel pump diaphragm
Changed fuel lines on motor and tank
Changed O rings on fuel fittings
Changed the starter gear-broke last week
Changed spark plugs
Changed Impeller
Reset the Idle screw so the line matched up with the roller
Bought a used repair book to help guide me
JerryJerry was a big help!
Chrysler outboard dude from youtube was a big help too!

So after all this I reset the carb out about one turn and the beast wanted to fire on pull 1! A couple more pulls and she did!
Could not keep it running without pumping the primer bulb every 30 seconds or so.
Made some minor adjustments on the carb and was able to keep it running. Made some more adjustments in Neutral and in Forward to the point where
it seems ok.

It idles in Neutral at about 2500 rpm and in forward at about 3000 rpm. I can drop this down but then I get to much vibration and inconsistency in performance.
Does this seem to fast of RPM?

Temperature on both cylinders outer walls seemed normal around 80-90 degrees and not to hot to the touch.

The motor seems to have strong acceleration and good reaction time. Just testing in a barrel for what that is worth.

Plan:
I am going to heat up all tank fuel lines to get a better seal at all the connections.
I will take out the plugs tomorrow and see how they look.
I think my fuel mixture has to much oil even though it's 50:1 A little to much smoke.
I will rerun it all again tomorrow to see if anything changed.

Any suggestions or guidance is always welcomed!

Thanks for reading
Pat

Idles "about" 2500 3000???
Idle should be about 1000 in N and 800 in gear.
They sell an item called "Tiny Tach" bolt on tachometer.
That way no guessing.

Most motors/carb air screw is set around 1 to 1 1/2 turn out.
Then adjusted from there.

Pumping the ball to keep running: that could be an air leak in the fuel line or the pump assy???

Too much smoke: when you try to start and it doesn't run right away, this leaves excess oil residue and it needs time to burn it off.
Once it runs for a while and the motor comes up to temp the smoke should decrease.
This motor probably doesn't have a thermostat so it won't ever get real hot.

Ok went back to it today:
Heated each external fuel line connection and tightened each up along with fuel lines on motor
Drained fuel and replaced with a leaner mix which cut down on the smoke by a fair amount
Took out plugs from yesterday and they were very very dirty....almost like gunk on them
Water in barrel was also filthy with some residue sticking to motor

Ran the motor and still can't keep the motor running so I had to elevate the fuel tank to above the motor and motor ran.

I did use a tachometer yesterday and today. The best I could get was around 1500 rpm in Neutral with reasonable vibration.
This is at about 2/3 rotation out on carb. Stalls out if I turn in or out or reduce speed.

I sprayed some sea foam into carb to try and see if that would help and this produced a fair amount of smoke.

After running today seems the plugs are less dirty.

Plan for tomorrow is to run the motor some more and try and get the idle down and problem solve the fuel issue. I may take the fuel pump off just to make sure there is no rips. I will change the water i am using as well.


Any other tips? Could it be that the motor needs a good running out on open water to get it cleaned and idle down? Run more seafoam?
The fuel supply issue is very frustrating.

Thanks,
Pat

Seafoam? that makes it smoke.
Use regular gas with the right amount of oil.

50:1 is the mix to get proper lubrication of internal parts.-------Many folks are misled by " smoke " on a 2 stroke motor.-----There are oils that are formulated to show less smoke.------Idling at 2000 RPM is way too high and you will ruin the gears and clutch dog soon.

Ok so here is where I may have a learning moment.

Tried a lot of different adjustments to get the idle down and it just won't go any lower without cutting out......

I was using a tachometer(30 years old) that was for cars(4 cycle) and what I believe is happening is this tachometer is recognizing a spark on the outboard (2 cycle) and doubling the result to the screen.
My son came home and we ran some tests using a multimeter and came out with somewhere in the 600-800 rpm range. We may test some more on Sunday.

The engine sounds normal in idle and in gear so that is a good sign. If it's not the 4 stroke 2 stroke issue then there is probably something off with my 30 year old tachometer.

I am ordering a small Tachometer to install on the motor so that will eliminate any issues as well.

Will keep you posted.

Purchased a small Tachometer and was super excited that I could now see what was going on. Motor sounds normal and it shifts gears pretty smoothly.
Turns out this tachometer is seeing 1500 rpm too. The settings are correct but the result did not seem correct.

So our curiosity has been peaked!!!

My son brought home a lab in a box they use at his university to help diagnose the issues we are seeing on the Tachometers.
Below is what he has said and we have included a couple of pics of the data points. The tachometers are picking up additional signals on each cycle(firing).

[The tacometer was reading something that had to be too high and we didn't really trust the old one.To just simplify the whole process we hooked up a little handheld device that could measure and plot the
voltage passing through our tacometer coil (basically an oscilliscope kinda). From there we just manually counted the
troughs in our signal and divided by time to get our revolutions per second. ]

Thought I would share this in case anyone else has seen this or thought it might be interesting. We are taking the motor out later this week and I will report back how it ran.

Well we got it out on the water with our old boat and we stayed up river just in case!!!!
The beast ran really well. Pretty quiet and pretty smooth.
Acceleration was very good and just smooth the whole time.

Took plugs out after and they looked pretty good.
We are heading up north of Bancroft Ontario this weekend
to run it for a couple of days.

Enjoy !!!!