Yamaha 50 tlr prime start test

[Harry1959]

Hey Guys, I have a 2008 Yamaha 50 TLR 3 cylinder 2 stroke. The prime start or fuel enrichment lever that goes into middle carb has 3 settings. On, run (or auto) and off. Starts right up in run mode just like it should, but runs rich and has no power if I leave in the auto mode. If I turn the lever off, manually shutting off the extra fuel it will run great.
I pulled the prime start assembly from that middle carb and hooked 12 volts to it. The needle(designed to cut off the extra fuel) only moves out 1/8 inch. The best video I found for how to test is by "Dangar Marine." They said that one manual indicates that needle needs to travel 1/4 inch to be good. They said a different manual says that any movement at all is a good test. So one book says mine is good and another one says it's bad. If anyone has experience with testing this or even another manual that covers testing it, I would appreciate you sharing.
Thanks Harold

 

[99yam40]

How long did you have it hooked up to 12V before remeasuring?

you need to get a service manual for your motor, not some other motor

 

[Harry1959]

Phi

How long did you have it hooked up to 12V before remeasuring?

you need to get a service manual for your motor, not some other motor

Thanks for the reply. I left power hooked up for about 10 minutes. Long enough and the needle had stopped extending. I must not have been clear enough in my original post. I don't have a manual for the 50 tlr and I asked if anyone had a manual or experience testing the Yamaha "Prime start system".
Danger marine is a company that gives a lot of outboard repair help on Utube. Their mechanic did a tutorial on testing and replacing this of prime start system. He has two different manuals for the Prime start system and says the two manuals that he has gives different specs for needle movement.
Again, if anyone is familiar with testing this system or has a manual with the specs in it, I'd appreciate you sharing the info. The part is $200 and I am on a fixed income so I try to avoid throwing money at any of my outboards. Thanks again

 

[99yam40]

all I can say is, if it moves but does not close off as it should then it needs replacing if you cannot figure out a way to adjust the thing to get it to move farther.
have you checked to make sure the diaphrams in the pumps are not leaking and adding extra fuel also

 

[brodmann]

I watched that video too. My son has the same motor, but his is a 2003TLRB. the "B" is used on year models where there is a significant change from previous models. That change in 2003 included that priming system. It's a pretty neat concept, but my son just started having problems with cold starts and then running too rich after a few minutes of warming up. We disconnected that thing and simply adjusted his "idle enrichment" screws on each carburetor. On the top of each carburetor on the starboard side is an adjustment screw. At the factory, they set these screws by screwing them all the way in and then backing them out 1-1/4 turns. They report that this adjustment is actually very lean, but it's done that way to meet current EPA regulations. Then they put that priming system on to feed extra fuel for the first 5 minutes to make the motor crank and run. Try adjusting those screws out another 1/2 turn and I think you'll be a happy camper.

 

[99yam40]

Just looked and that part number is for a 40 and 50 from 95 on up.
See if you can find a used one

The manual for my C40TLRX does not give a spec just replace if it does not move.
so maybe you need to be looking for a different problem

 

[Harry1959]

I watched that video too. My son has the same motor, but his is a 2003TLRB. the "B" is used on year models where there is a significant change from previous models. That change in 2003 included that priming system. It's a pretty neat concept, but my son just started having problems with cold starts and then running too rich after a few minutes of warming up. We disconnected that thing and simply adjusted his "idle enrichment" screws on each carburetor. On the top of each carburetor on the starboard side is an adjustment screw. At the factory, they set these screws by screwing them all the way in and then backing them out 1-1/4 turns. They report that this adjustment is actually very lean, but it's done that way to meet current EPA regulations. Then they put that priming system on to feed extra fuel for the first 5 minutes to make the motor crank and run. Try adjusting those screws out another 1/2 turn and I think you'll be a happy camper.

So, are you saying to leave the prime start intact and back off 1/2 turn on each of carb jets? I'm certainly willing to try that. You said you disabled your sons prime start? I use my boats in the winter here in Ohio and it seems like I'd have some major issues with cold starts. Mine doesn't start now when cold with the prime start in closed position.

 

[Harry1959]

Just looked and that part number is for a 40 and 50 from 95 on up.
See if you can find a used one

The manual for my C40TLRX does not give a spec just replace if it does not move.
so maybe you need to be looking for a different problem
View attachment 386618

Thank you very much for looking up and verifying the part numbers being the same for your 40 and my 50 and for looking it up in your manual. It did look to me like there was an older and newer part number. It does sound like I may need to look at other things. As Brodman suggests, I will revisit my individual carb jet adjustment, but It sure runs perfect if I cold start with in auto/run and then manually turn it off after it starts. It's just PIA to take cowling off and on every trip when I first get to the lake.

 

[99yam40]

If the fuel pump is leaking into the crankcase, it would cause #3 cylinder to run rich.
I am not sure if any other cylinders would be affected.
I do not remember off hand where the pump in the prime start system gest its pulses from, but it might be #2.
would not hurt to check to see if those have a problem

 

[99yam40]

I just had a thought, have you verified that the prime start system is getting voltage to it while the motor is running?
and that the ground wire is making good contact.
if no power to it it will not heat up and close off.

 

[Harry1959]

I just had a thought, have you verified that the prime start system is getting voltage to it while the motor is running?
and that the ground wire is making good contact.
if no power to it it will not heat up and close off.

Yes, I did verify that it's getting power to the prime start, and the unit is grounded. I should have mentioned that in my OP. Good thought! I probably will buy a manual as you suggested. I usually get by without one, with all the help online.

 

[brodmann]

The only solution I can come up with is like you say take the cowling off, turn prime system on, start and let warm up, turn primer system off (so it doesn't run too rich), put the cowling back on and go. Or, you could run wires to a switch on the console to turn the primer system on and off. Odd solution, but it should do the trick. I guess it depends on whether this is a "take the wife and kids for a nice day out on the boat for a pic-nic" boat, or a "blood and guts on the floor" fishing boat, as to whether or not you want to run more wires and drill a hole to mount a toggle switch in the console. I certainly understand that distinction! I've owned both types of boats. My current boat is more of a "take the wife for a boat ride to meet the kids and grandkids on an island somewhere for a day in the sun swimming, finding shells and sharks teeth and eating watermelon, boiled peanuts and having a late afternoon weenie roast" kind of boat. I'm good with that. My 3 sons take me fishing on their boats!!

 

[99yam40]

No it is not an electrical switch, it is a manual turn device.
so it cannot be remotely operated.

OP make sure you are turning the emergence switch all the way counterclockwise to the auto position.
if turned to the on position the needle cannot turn it off when warmed up.

 

[Harry1959]

No it is not an electrical switch, it is a manual turn device.
so it cannot be remotely operated.

OP make sure you are turning the emergence switch all the way counterclockwise to the auto position.
if turned to the on position the needle cannot turn it off when warmed up.

Picture of mine attached, it's as you described. I always start it in the
normal position(counterclockwise) and give it 5 minutes to warm up and it runs like crap until I turn it to closed position,( all the way clockwise). Then it runs kind a champ the rest the day. At times I've given it longer to warm up in the normal position and it just doesn't shut off the extra fuel until I close that red valve manually. I

 

[99yam40]

Yes, I did verify that it's getting power to the prime start, and the unit is grounded. I should have mentioned that in my OP. Good thought! I probably will buy a manual as you suggested. I usually get by without one, with all the help online.

how did you verify that it was getting proper power?
Setting up a current meter in series to the heater unit would verify it was getting good connection and current was flowing

 

[Harry1959]

how did you verify that it was getting proper power?
Setting up a current meter in series to the heater unit would verify it was getting good connection and current was flowing

I unplugged the blue wire (+) where it plugs in back near the power head and connected my voltage meter to the wire coming from the power head area. When I started the enginge I had power going to the prime start.
Which company printed your service manual? Thanks

 

[99yam40]

 

[Harry1959]

View attachment 387537

Hey 99, thanks again for taking time to help. I did purchase the 50 tlr manual as you had suggested.
I took that prime start apart and reassembled for the 3rd or 4th time last week. I didn't think I found anything, but when I took it out this past Saturday it functioned as it should. I'm thinking that I must have been binding the selonoid up when I put in the carb on previous attempts..... that or there was a loose wire or something that I jiggled. I'm betting that I was putting it in just slightly cocked. Anyway, thanks again