50TLR 2005 No WOT after warm up

[marinermikes]

I have a 2005 50TLR that runs fine for the first twenty minutes. Stop the boat let it sit for a few minutes start it back up and it won't take the throttle. It gets progressivly worse the longer you run it. No buzzer.

Turn it off let it sit for until cool and it will run fine again.
Very low hour motor. New water pump and the thermostat works fine. It's not over heating. I tested the buzzer and it works fine. And the carbs are clean as a whistle.

Pumped the fuel bulb. It was hard and it made no difference. Pushed the choke, again no difference.

I pulled the sensors out of the head and left them cool to ambient temerature, no difference.

I got it running and unhooked the timing arm on the CDI and it helped a little when I moved it manually. It acts like as soon as the CDI gets warm it fails.

Any help would be appreciated. Thanks Mike

[marinermikes]

I also tried a external tank with a new hose. Same thing. It really is pointing to the CDI. It's the type with the timing arm on it. Is it out of the question that it's failed?

[marinermikes]

Ok, Lets try this. If I know thw carbs are clean and the motor runs good for twenty minutes, if the motor was starving for fuel would not pumping the bulb make it run even if something was wrong with the fuel pump? Anyone?

I'm trying to convince myself here that there is something wrong with the CDI box.

[markonthebeach]

fuel cooler

check your water flow through the fuel cooler?

[markonthebeach]

I'm sorry, you said carbs. I thought this motor was EFI.

[marinermikes]

markon, Thanks for the reply at least. This motor is driving me crazeir than I already am. It will not do this at home, only on the water. I hate to spend the money on a CDI only to find that's not it.
I seem to have elliminated everything else. It's a simple motor, no computer. I guess the next step is to take it back to the water and put a timing light on it the next time around. Should have done that the last time.

[marinermikes]

Is there anywhere I can send this CDI to be tested?

[99yam40]

No, I have never heard of a way to test one off of the motor.
Best thing to do is test the inputs and out puts of the CDI and the coils/wires to make sure they meet the specs in the manual and see what changes when warmed up and causing your problem. could be a charge coil or pulsar coil that is going bad you will not know till you test things
The Yamaha service manual and the proper testing equipment( a peak reading meter made for these ignition systems or a DVA adapter and regular voltmeter) will be needed. A timing light will help some too.

If all this shows to be good even after warmed up the look at the fuel system.

[marinermikes]

Thanks for our reply. I will check the inputs to see if they are in spec. I really don't think it's the fuel system because it runs great for a couple of miles or until you turn it off and sit and pumping the primer bulb makes no difference, This motor starts a little hard also. Is it suppose to have a fast idle when you first atart it? Another question. Can you manualy choke it?

[99yam40]

If you read up on your motor you should find that the timing will advance at start up to increase the idle as long as you do not raise the idle lever on a prime start system. And if it is a prime start then all you can do is fix the carbs or prime start system for proper starting

[marinermikes]

After reading various threads about the start primer. I think the problem may be that the red lever behind the carb cover may be in the wrong position, I took the cover off becaue I could not read the position print with it on and I'm still confused as to what's open and what's not or where it should actually be. I'm assuming that open is when you turn the lever the stem pulls out? Where should this be for running? The last time I tried it on the water the long arm was in the three oclock postion. Thanks Mike

[jimclemjr]

My first post and not a mechanic- but from my experience on a 40 TLRT about ten years older-when prime start screwed up it is all about starting- Your 20 minute issue and verification of fuel leads me to think about the way heat can cause an electrical coil to internally expand and break wire continuity and then when cool it closes the gap to complete circuit again. Other electrical parts can do the same. If you suspect the fuel pump, short of replacing for about $35, put some ice on it for a few minutes and see if that doesn't help. Try some ice on the outside of the CDI as well just make sure You have it in a baggy to not wet it down.

[99yam40]

After reading various threads about the start primer. I think the problem may be that the red lever behind the carb cover may be in the wrong position, I took the cover off becaue I could not read the position print with it on and I'm still confused as to what's open and what's not or where it should actually be. I'm assuming that open is when you turn the lever the stem pulls out? Where should this be for running? The last time I tried it on the water the long arm was in the three oclock postion. Thanks Mike

Have you tried to read your owners manual?
It should tell about the prime start system.
On my C40TLRX normal is when the red lever is turned counterclockwise, open is one notch clockwise and closed is all the way clockwise as far as I can remember, but there is a sticker on the silencer that shows the positions

[marinermikes]

I just got the motor and I don't have a manual for it yet. I did send for one but haven't got it yet. There is no label for the position it's cast into the aluminum housing behind it. It's so small that I had to take the air box off to read it. Even then I could not figure out wich way it was suppose to point.

I cleaned the carbs when I first noticed this. No help and they were as clean as a whistle. I'm actually a Johnson Evinrude mechanic so this auto primer starter is new to me. I'm going to take it out tomorrow and try the lever in a different position and see what happens. This motor can't have twenty hours on it.

I did switch it to closed and put it on the muffs and started it. It did what it was suppose to do. Started at a little higher idle and then after six to eight seconds idled down.

If it doesn't work tomorrow I may try the ice trick. Thanks I do appreciate your time. Mike

[marinermikes]

Well I took it out today and it still does the same thing. Traveled for two miles up the river, turned it off and sat for five minutes. Started it back up and it would not go to full throttle. The more I run it the worse it gets until all I have is idle.
It acts like the spark advance isn't working and unforunatly I forgot my timing light at home.
I'm going to start it here at home and let it run with the hood on until it's good and warm, put the timing light on it and fiddle with the throttle and see if I get the mark to advance.