1999 Yamaha 4 stroke F50TLRX running rich

[pstephens46]

You guys kill me with the prices on boats down there...I wouldn't get the used trailer for $1500 up here. Nice boat, how long is it?[/QUOTE]

He got some kinda deal. Pricing has gone wacko here too. I priced a new aluminum trailer couple years ago. $4200. Boat trailer is basically nothing, a rail job. Used horse trailer? $11000.
22 ft Sportsman Bay Boat? $68000 New. Sportsman mind you....

[ChuckB1954]

What is the exact model/serial number on the ID tag which is on the transom bracket? I think I have the proper Yamaha manual PDF...

Have a fire tonight on the beach and light it with the Clymer manual.

I would love to have a better manual if this one sucks!

The transom bracket has a lot of corrosion. The only numbers I can read on the tag clearly are the last 2 that show the year. RX=1999..

[boscoe99]

this must be one of those motors that Rodbolt said was a nightmare/overly complex

Rube Goldberg comes to mind.

[99yam40]

this must be one of those motors that Rodbolt said was a nightmare/overly complex

[panasonic]

What is the exact model/serial number on the ID tag which is on the transom bracket? I think I have the proper Yamaha manual PDF...

Have a fire tonight on the beach and light it with the Clymer manual.

[ChuckB1954]

It is 15' 2"

No, don't feel bad.. this was a rare opportunity.. Owned by a friend of a friend. My friend called me out of the blue at about 6 PM and said "Stop what you are doing.. go buy this boat.. NOW!!" I owned it by 9PM

I Think I am going to bite the bullet and buy this now for $324.00.. all parts look to be there including the obsolete ones.. Plus many extra carb parts.. Am I crazy? I haven't even checked the compression yet..

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[panasonic]

Some of the mounting parts may not be available now. I would go to the scrap yard and see what they got.

If worst came to worst I would rig a choke cable out to the engine pan and manually operate the choke plates. You are not far from the engine in that boat.

You guys kill me with the prices on boats down there...I wouldn't get the used trailer for $1500 up here. Nice boat, how long is it?

[ChuckB1954]

looks like a new trailer that would cost that.

has to make me wonder if the person you bought it from ever ran the boat if the pieces are long gone

It's a long story.. to make it short, this is what the boat looked like not too long ago. His son blew up the 2 stroke shown and bought the four stroke. He put it on the boat and said it never ran right. He decided to just get rid of it and buy a new boat. He never really used it with the "new" motor. He rebuilt and painted the trailer right before he got rid of it.


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[99yam40]

looks like a new trailer that would cost that.

has to make me wonder if the person you bought it from ever ran the boat if the pieces are long gone

[ChuckB1954]

Here are all the loose, unconnected wires under the cover (maybe I missed some). I am hoping they are the ones I need for the missing components. My neighbor just happened to have a nice Clymer Yamaha outboard shop manual and just gifted it to me. I should be able to figure the wiring out.

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[ChuckB1954]

I would be asking the people that sold it to you where the rest of the parts are

Those parts are long gone.. Not really complaining and don't mean to brag, but I only paid 1,500.00 for the whole set up shown in the picture.



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[ChuckB1954]

Looks like the "solenoid coil works" has a large, pull spring below it.

With the direction of the fuel flow arrows, it appears the spring holds the choke butterflys open and the solenoid closes them when activated...

As noted, missing those parts, the choke butterfly can flop around, open and close at will...

I am pretty sure replacing those parts will solve my engine running rich issues, but we'll see.

When I first got the engine (came with the boat) I notice that I could work that choke linkage by a push of my finger.. no resistance. I'm sure it was flopping around.

[ChuckB1954]

Chuck....you need those parts on the engine to make it run properly as designed

Yes sir I do. I simulated the prime starter just now and realize just how critical it is. It will be the easiest to replace. The solenoid will be a bit more difficult with all the small pieces.

[ChuckB1954]

Only one solenoid is used. Please help me understand how two are missing? Or are you saying that both the solenoid and the Prime Start thermoheater are not installed on the motor? #9 and #36 in your illustration?

Thanks for the pictures and info!

Yes, both the solenoid and the Prime Start thermoheater are not installed on my motor.. I mistakenly identified the part. I assumed.. two wires.. must be some type of solenoid.

[ChuckB1954]

For everyone as well: https://www.boats.net/catalog/yamaha...arburetor-link

You SHOULD have Prime Start, for cold start up (enriches the mixture), part #9.

I believe, that part missing (missing) would cause a rich condition. Someone else will have to chime in to confirm..


Looking at your picture (not so clear), it appears you have choke butterfly linkages, is that correct???

It shouldn't per the parts site: https://www.boats.net/catalog/yamaha...lrx/carburetor

The poor picture was captured from a video I made of the engine running. It was too late to go outside and take a decent one.

Took a closer look just now.. I can see how the prime starter assy could make this engine run rich. Without it, the choke linkage is flapping in the breeze and closes any time you give it throttle. I held the linkage contact point that the prime starter pushes on and not only does it stabilize the linkage, the choke doesn't move when you give it throttle unless I backed off that contact point.


Prime starter contact point:




As far as the choke linkage, see my first post.. it is shown in that diagram. ( https://www.boats.net/catalog/yamaha...arburetor-link )
here is my linkage: