2003 yamaha 90 power lost after running

[Alan327]

I have a 03 yamaha 90 2 stroke and it runs fine for a little bit and then will bog down to 2200 rpms and some times it will go back to running fine and then some times it will not and I have to limp back to the dock. I have tried every thing new plugs, drained tank and cleaned, had the carbs off and cleaned and still no help cah anyone help

 

[99yam40]

Re: 2003 yamaha 90 power lost after running

Make sure your alarm functions properly.
That way you can tell if it is overheating or having oil issue causing it to go into a safe slow mode.

 

[Alan327]

Re: 2003 yamaha 90 power lost after running

I checked the alarm and it works fine is there a way to test the oil tank sensor? or a way to buypass the sensor to make sure thats the problem or not

 

[robert graham]

Re: 2003 yamaha 90 power lost after running

sounds like a fuel delivery problem. Check entire fuel system starting at pick-up in fuel tank, fittings, primer bulb, quick-disconnect on front of cowl, fuel filter, fuel pump. There are several check valves in the system that have to work properly. Also air in-leakage around quick-disconnect or hose connections can give problems. There are check valves in the fuel pump and primer bulb which may get stuck. Hope this helps and good luck!

 

[99yam40]

Re: 2003 yamaha 90 power lost after running

I checked the alarm and it works fine is there a way to test the oil tank sensor? or a way to buypass the sensor to make sure thats the problem or not

I am not sure what all will send your motor into safe mode and how to test everything, You need to check your manual and go from there.
If you have a timing light, you can check the timing when it happens and see if the timing is being retarded by the CDI. That is the way it slows down and restricts the RPMs.
You can check the fuel pump pressure and vacuum to see if you are having a fuel delivery problem

 

[Blue_Dog09]

Re: 2003 yamaha 90 power lost after running

Hi Allan

M8 i had the ezack same problem had it fixed week ago it was a CDI BOX nothing to do with your fuel m8 trust me iv done every thing to do with fuel and still had the problem a second hand CDI BOX FIXED IT

ps m8 there bloody not cheep good luck.

 

[robert graham]

Re: 2003 yamaha 90 power lost after running

I still believe it's most probably a fuel delivery issue but hopefully you'll let us know what it turns out to be, especially since I run the exact same motor. Good Luck!

 

[Alan327]

Re: 2003 yamaha 90 power lost after running

well i will try a cdi box because i replaced all fuel lines new ball every thing that fuel flows true because I thought that was my problem I will try to locate one and I will let yall know thanks for all the help I want to fix it because it only has 159 hrs on it and i want to sell it so i can go biger i need to go faster than 35 so i am going to step it up to a 150hp so if that fixes it it will be up for sale if anyone is looking

 

[rtark]

Re: 2003 yamaha 90 power lost after running

I had the same prob with my 1998 P40 TLHW 2 stroke, got it fixed yesterday. Mine would fall back then surge at WOT. Before I got back to the ramp (5 miles) it was a lot worse. While it was still on my trailor in the water, I reved it up in gear and then I unplugged ( not with bare hands) the #1 plug wire, it almost died. Then I did the same with #2 wire, no difference and #3 wire was very little difference. My prob was with the 2nd and 3rd cyl. When I got home I checked the fire and it was perfect. In short, it was the fuel system. There is a diapharm on the side of the #2 Carb that had a hole in it. This diapharm feeds gas to the # 2 and 3 Cyls. Cost, about $10.00. I looked it up and the 2003 90hp has the same part nimber 6H3-24411-10. see it here
http://www.boats.net/parts/search/Yamaha/Outboard/2003/90TLRB/CARBURETOR/parts.html

Hope this helps..Ray

 

[Alan327]

Re: 2003 yamaha 90 power lost after running

i will go get one and try that first thank yall so much for all the help if theres anything i can do for yall let me know i am a ase auto tech you can email me at Mrfixcars@aol.com in the title put from Iboats so i will know you

 

[99yam40]

Re: 2003 yamaha 90 power lost after running

As a auto mechanic you should know that replacing parts and hoping it fixes the problem is the most costly way to repair things unless you get lucky and find the right part to replace early in the game.
Testing is the way to go with a manual and looking at the frequently ask questions part of this forum for testing things helps a lot also.
I would agree that a hole in the fuel pump diaphragm may not show up in the pressure/ vacuum test but it will eliminate most other fuel restriction problems.
There are tests for the firing components in the manual also, use them.

Sorry for the raving, just my 2 cents, even if they are not worth the 2 cents

 

[Blue_Dog09]

Re: 2003 yamaha 90 power lost after running

hi allan

so how did u go with this problem m8 u sort it out ?

 

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