50TLR 2005 No WOT after warm up

[marinermikes]

Ok. I put the motor in a barrel and left the hose run slow in it. I ran it for forty minutes at an excellerated idle with the cover on. The engine was as warm as it's going to get. I did some tests on the CDI. It never faultered. The timing mark on all three cylinders were right on. It never misfired. I disconnected the timing arm on the CDI and manually advanced the timing and the marks moved as they should.

I now know where the marks on the choke lever are suppose to go. The last time I had it out I tried running it in the emergency postion an in the normal postion. Never tried closed. I tried all three postions in the barrel and it ran best in the closed postion. Back to the river to try it. If it will only run inthe closed position I will assume that there is something wrong with primer.

[marinermikes]

I took the boat out a couple of weeks ago and ran it for a hour with the hood off. Starting and stopping full throttle to idle. No problem. I put the hood back on and travel about two miles, turned it off, waited ten minutes, started it, slowly went to full throttle and it promptly failed. Nothing more than idle, any throttle at all it would stall. Checked the carbs by taking out the drain plug. They were full. Unplugged the sensors. No help.

I disconnected the timing arm and advanced the timing by hand just a little and the rpm's picked up. I then had my friend give it some throttle at the helm and the rpm's picked up a little more. I advanced the timing all the way while he slowly gave it full throttle and off we went. Rode around for another half hour with the hood off. Ran great. Put the hood back on ran it for a while and it failed again.

The new CDI came a couple of days ago. I installed it today and took it out. Ran it for a couple of hours, It ran way better and never missed a beat. Problem solved five hunderd and forty dollars later. A motor with not more than fifty hours on it.

[99yam40]

That may have been found simply by hooking up a timing light to see it the timing was doing what it was suppose to while problem was occurring, but how know for sure

[marinermikes]

I tried the light Yam. It was fine until the problem arose and then nothing but idle. At idle the timing light showed all cylinders were firing. the problem was that as soon as you would give it any kind of throttle it would quit before I could get any kind of reading. I don't know what the outputs were when it failed.

I do agree that the best way to find the problem is to test when the problem occurs. In this case it was hard to do.

I disagree with the timing being in with the CDI. The CDI has capacitors in it when one goes bad and you lose spark to one cylinder you need to replace the CDI( $540.00). When you add a moving part to it like the timing advance you have one more thing that can go wrong with it. All moving parts like reostats go bad. So now you have another item that if it fails is going to make you spend a bunch of money.

I was nervous about the CDI. Sweating bullets that I didn't waste $540.00

I'm not picking on Yamaha. I believe that all outboard manufactures have made them way to complicated.

I have a small outboard business and have rebuilt many. This is my first Yamaha. I own five boats with my own rebuilds on two of them. I also fish alot of touraments and run all older outboards. I carry a spare power pack at all times. I can fix anything on the road unless a rod comes out through the block( never happened). I believe simpler is better

At $540.00 for the CDI I can not carrry a spare..

I guess I'm just an old school fool.

I do appreicate your input. You are a valuable asset to this forum. Thanks Mike

[99yam40]

I believe that motor has 1 charge coil that charges up the capacitor in the CDI and 3 pulsar coils to tell it when to fire the different plugs. I am not really sure if there are more than 1 capacitor in the CDI. If the inputs and outputs are measured like the manual states at the different RPMs I would have thought it would have shown something out of spec if there was a problem, especially if measured after warmed up.

If it only has 1 cap then if it shorted when heated up that would make some sence of why it was dieing instead of 1 or2 cylinders start missing.

Yes it would have been nice it the TPS was separate as that is all I needed on mine

[MJohnston7]

Great information MarinerMikes. I have the same exact problem. I want to thank you for taking one for the team and buying the CDI first. Glad to hear it fixed the problem, but sorry for the cost. I'll be ordering mine this weekend.

[marinermikes]

I believe that motor has 1 charge coil that charges up the capacitor in the CDI

I'll bet your right. Johnson/Evinrudes have one for esch cylinder but I believe that you are correct that Yamaha's have one. Explains alot.

If you are going to repalce one of these make darn sure you have checked everything else. Fuel, timing so on. You really don't want to take a five hundred and forty dollar guess.

[99yam40]

overheat and/or low oil level will cause the timing not to advance
That is how they limit rpm

[metricyamaha]

I believe that motor has 1 charge coil that charges up the capacitor in the CDI

I'll bet your right. Johnson/Evinrudes have one for esch cylinder but I believe that you are correct that Yamaha's have one. Explains alot.

If you are going to repalce one of these make darn sure you have checked everything else. Fuel, timing so on. You really don't want to take a five hundred and forty dollar guess.

I have a 2005 50hp TLR two stroke. It is similar to yours. It has a charging coil for the CDI, lighting coil for charging and 3 pulsar coils.

After replacing the CDI some time ago, I had misfiring problems on idle and low RPMs. I'm still looking for some kind of solution, and I took apart the carbourators 3 times already.