Yamaha Pro 50, ironing out the kinks

[TownsendsFJR1300]

Not really as a solenoid when energized is a electo magnet and instantly moves the core and rod.
the heater unit slowly heats up and caused the wax pellet to expand slowly to push the needle out slowly
they are tested differently

OKAY..........

[Pat Gidley]

Question for y'all. The way I understand the prime start, that not-a-solenoid/valve thingy works independently. On my control unit, the choke switch creates a very clear click at the motor, and holding it on will very clearly drop the rpms/stall the motor. Any idea what that is con*****ing? It doesn't have a choke, but the switch sure does something.

Anyways, the thermostat made a slight improvement but still stalling out. It'll idle down fairly nicely, then just kinda drops rpm and stalls. Still thinking it could be that prime start assembly, but when I pull the carbs to change that gasket I'll give the whole fuel system a what's-for. Kind of unscientific way to do things, but there's a demon in there that needs to be exorcised.

I can borrow a timing light from a buddy. How do I check timing at 25 degrees? In neutral on muffs with the fast idle lever? The sm does a crap job explaining.

[greasyshaft]

it's a solenoid

check all the linkage lengths and verify that the throttle arm is hitting the WOT stopper.

or hang off the the back of the boat with a timing light at wot

or test prop

or fix the fuel system

[99yam40]

Well it sounds like the solenoid you have may inject some fuel like the old 35 Johnson I had when pushing the switch maybe or it just lifts a needle off a seat. I really have no idea how or what that does on that older motor.
You should be able to tell if it is clicking, what it does if you look at it when out and you hit the switch.

On my 1999 C40 I marked where the Wiper on CDI(timing/throttle position lever) was at at High RPM (motor not running) disconnected the linkage to the wiper. fired up motor and then let it idle checked idle timing with light and then mover wiper/linkage to where it should be at high RPM and checked with light where it was showing the timing was.

It can be done while running at speed on the water without undoing anything but the cowling, but you need someone to be running the boat while you check the timing

[greasyshaft]

Think of it is a manual prime start system

[99yam40]

Think of it is a manual prime start system

So does it just lift the needle off the seat to allow extra fuel to be sucked into the intake?

Or does it open up a passage and allow extra fuel to be pumped into the intake with a diaphragm?

Edit, Looks like it does have diaphragm and check valves for a pump action

[Pat Gidley]

Interesting, so it would make sense if that diaphragm is allowing fuel into the intake manifold and stalling it out. Once those parts come I can be sure.

Reason I was asking about timing, the wiper on the CDI hits the 5 deg (lowest mark on the cdi) and 25 deg as per SM, but if I disconnect and advance to 1 deg (second mark) while at idle setting on the carb, I can back the idle speed down more smoothly with the adjust screw.

Agree it seems like fuel, but want to eliminate that rabbit hole.

[99yam40]

Check timing with a light to see where it is sitting at idle. and at high speed timing

I had to change my CDI to get the idle timing corrected
It was retarded too far at idle but fine on WOT

when working properly on my C40TLRX I found that it starts at a different setting and once motor warms up enough it closed a switch and it goes to the the idle timing spec.
Advance the throttle and it advances timing up to the spec for that

[Pat Gidley]

Well seems like case closed. It was the timing. The first mark on the CDI wasn't advancing to 5 degrees when at the first hatch mark. Set the stopper screw to the SM specs using a caliper and checked timing at idle. Timing was right in spec with the light. Launched the boat and it ran great.

Need to fine-tune the carb pickup, and I'll still swap that diaphragm when the part comes. But the stalling problem is gone.

Thanks for all the help friends.

[99yam40]

Check the high speed timing also.
Want to make sure it is in spec too

[TownsendsFJR1300]

Excellent and thanks for the update!!