1999 Yamaha 4 stroke F50TLRX running rich

[ChuckB1954]

Installed the missing parts on my motor (prime starter assy, solenoid coil) Took about 1/2 hour getting the plus lead from the solenoid armature connected to the carb linkage.

20190530_183402-small.JPG

Plugged everything in to the correct existing leads as per the wiring diagram:

20190530_184235-small.JPG
carb wiring.JPG

Thought by flipping the toggle on the controls, that the solenoid would react, but nothing happened.
20190530_185508-small.JPG

Had to quit for the night, but I am getting there. The blue wire and the green/white wire coming from the main harness is how both components get power. Maybe the prime starter is how it should be, but I would think that I should be able to work the choke solenoid from the toggle switch, although I could be completely wrong. The 703 controls are from the old C55TLRS 2 stroke motor that was on there. I need to check out the wiring diagram closer.

[99yam40]

Being called prime start, I would think it should be automatic operation.

Not many know about those F50 motor setups

[panasonic]

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[panasonic]

A 1999 F50TLRX uses both a prime start assembly (thermoheater) and choke plates. The thermoheater in this model is causing the choke plates to open or close. It does not work like other PrimeStart components on other models. During the start the solenoid is energized and this also causes the choke plates to close.

Two strokes can have PrimeStart. Carbureted, EFI or HPDI.

Four strokes can have PrimeStart. Carbureted, EFI or Direct Injection.

A PrimeStart is not a PrimeStart is not a PrimeStart. It is a Yamaha term coined for automatic fuel enrichment. There are many ways and components involved to automatically provide fuel enrichment if and when needed.

f50 choke.JPG


Mr Boscoe because there is no information on the actual operation of this system, just how to test and adjust the different components. I am trying to figure out how this overly engineered start system works.

So when trying to start a dead cold engine, with key on, the choke solenoid is energized and the choke plates close....engine starts. After engine is started the "Electrothermo ram" is energized and after a period of time it allows the choke plates to open again.... this is done mechanically through linkages?

Once engine is warm enough to start on its own, without any enrichment, the "Thermo switch 2" prevents the choke solenoid and electrothermal ram to function?

But that makes no sense (thinking out loud) because the thermo switch 2 appears to be "normally open" and closes when warmed up.

You have anymore information on this?

[boscoe99]

Pan send me your email address

[ChuckB1954]

Mr Boscoe because there is no information on the actual operation of this system, just how to test and adjust the different components. I am trying to figure out how this overly engineered start system works.

So when trying to start a dead cold engine, with key on, the choke solenoid is energized and the choke plates close....engine starts. After engine is started the "Electrothermo ram" is energized and after a period of time it allows the choke plates to open again.... this is done mechanically through linkages?

Once engine is warm enough to start on its own, without any enrichment, the "Thermo switch 2" prevents the choke solenoid and electrothermal ram to function?

But that makes no sense (thinking out loud) because the thermo switch 2 appears to be "normally open" and closes when warmed up.

You have anymore information on this?

Ran out of time to run the engine, but I did spin it over to see if the solenoid would activate. It did not. I will run it tonight.

[TownsendsFJR1300]

Pan send me your email address

Please post on the forum, I'd (and apparently 99Yam) would like to know how this system works as well.


I don't think it falls under Rodbolts "stupidly simple" systems... WAY OVER COMPLICATED..

[rodbolt17]

plenty of info on this system.
it is overly engineered .
I like that.
I call it a rube-Goldberg system.
it was only used on the F and T 50's of the late 90's.
it is not quite a prime start yet not quite a full manual system.

[99yam40]

So, Rodbolt does that mean that he has to manually activate the choke at cold start(hit the switch)?

[panasonic]

Who the hell is Rube Goldberg? Never mind I looked it up..never heard that saying before...but it is a good one!

[ChuckB1954]

Who the hell is Rube Goldberg? Never mind I looked it up..never heard that saying before...but it is a good one!

Well old rube must have been smart man as it seems no one knows how this system works!

but it's really no big deal I'll figure it out myself as I always have done. Thanks everyone for their help. You have confirmed my suspicions and pointed out some things that I was not aware of.

[TownsendsFJR1300]

plenty of info on this system.
it is overly engineered .
I like that.
I call it a rube-Goldberg system.
it was only used on the F and T 50's of the late 90's.
it is not quite a prime start yet not quite a full manual system.

Job security for the mechanic that know's how it works.

Just more crap to break / fail down the road for the boat owner and / or the mechanic that doesn't understand it...
Two separate systems that will work on their own BUT, lets mix them together just because... Dumb...

KISS

[ChuckB1954]

Plugs a nice shade now!

Here is a section of my picture previously posted of the top carb. . Notice something wrong? A majority of my problem. Three carbs were like this.

spring.JPG

[TownsendsFJR1300]

Choke lever pulled when it shouldn't be?

IE, butterfly's CLOSED?

Is the system working correct now?

[99yam40]

3 of 4 carbs , must be talking about a link and sync problem