yamaha diagnostic codes

[robalo250]

I have a 96 yamaha vx 250 that i have been having motor bogging down issues past half throttle. I thought is was fuel related so i cleaned fuel system including carbs and changed out low pressure fuel pumps, all filters. I ran an external fuel tank in the boat with fresh gas. The motor starts and idles fine but it just acts like the motor just dies at around 2500 rpm even though it never shuts off.

I went and purchased a winky blinky and got code #33 until idle kicked down and went to code #34. My yamaha manual does not say anything about those codes except they are for the computer. My motor # is txru. Any help would be appreciated i don't want to spend my whole summer working on this motor and my boat sitting there.

[99yam40]

You might post exactly what you motor is doing because saying " it just acts like the motor just dies at around 2500 rpm even though it never shuts off " does not say much.
Is the timing changing?
is there loss of spark to some cylinders?
Does the alarm system and gauges work to make sure there is not something calling for RPM reduction?


This is the only link I could find for the Yamaha codes right off hand, and 31 to 44 listed as not faults. So maybe Rod will drop in and help you on the 34, but I think it is all normal, but I know not what I am talking about
http://www.yamahaoutboardparts.com/f...html#post56877

[robalo250]

sorry i will try to be more specific. At around 2500 rpm the motor just acts like it's bogging down then boat will not come on plane. It does seem to me like it's running out of fuel or leaning out bad. I have just a standard analog tach but the alarms all work and nothing sounding. I have no idea how to tell if the timing is changing or i am losing spark underway. I did check the throttle position sensor as per manual and closed it had .52 volts.
The motor sat all winter but was winterized fuel drained and stabil was used in non ethanol fuel.

[robalo250]

Just in case maybe this will help someone the code #34 is engine tilted up. My tilt switch must be bad. I bought a spare motor with a blown power head cheap so i will just start swapping parts until problem hopefully goes away. I am going on vacation in about 6 weeks to daulphin island alabama and would like to be able to go offshore. All local boat repair shops booked up for summer.

[rodbolt17]

code 34 on that motor is tilt angle recognition.
so far only used on 3.1L carbed motors.
fix the trim sensor or circuits.

[TownsendsFJR1300]

When you cleaned the carbs, did you PHYSICALLY PULL all the jets and visually check / clean them?

Some jets have horizontal holes that you CANNOT see unless you pull them.

Sounds like the mains are clogged.

If you don't want to pull the carbs, a good dose of Yamaha's "Ring Free" is an excellent fuel system and top end cleaner. Its not cheap, but 1 oz treats 10 gallons. I would probably mix it at twice that and run the engine..

[robalo250]

I pulled all the carbs removed the jets and soaked the carbs for a couple of hours in gumout solvent but they seemed clean. I put a timing light on the motor to check the timing and brought the motor up to 2500 with the muffs on but did not see the timing move. I realize with the cdi unit it is not like a mechanical linkage but shouldn't i see some change.

[99yam40]

pay attention to Rodbolt's post, he is a Yamaha master tech
there is a good chance if the ECU sees motor tilted too far then is may cause problems with higher RPM operation.
I do not this for a fact, but it could be a possibility.

[robalo250]

was told by a local mechanic that if yo run the boat and shut off the motor it should not take anymore than 2 pumps of the primer bulb to get it back hard or you have a obstruction in the fuel system. Is there any truth to that?

[robalo250]

Is there anything to that rodbolt? I will be off work on monday and change out the trim sensor.

[Sequoiha]

if you run the boat, you should not have to pump the primer bulb the rest of the day, Ive gone weeks with out having to pump my primer bulb,

[rodbolt17]

dunno about that truth.
would depend on to many variables.
ALL that stupid bulb does is prime the system.
if your old chebby got parked on its grill every night it would have had a primer.

there are some codes that will lock base timing.
timing is also dependant on throttle angle and engine speed.
once you get code 1 blinking then continue.

[Sequoiha]

Computer Self-Diagosis Code Table
Code
Problem Area
Code
Problem Area

1 Normal
8 Shift cut Switch
2 Crank Position Sensor
9 Warm Up
3 Thermosensor
10 Trim Angle Sensor Position
4 Trim Sensor
11 Pulser Coil
5 Knock Sensor
33-44 Micro Computer Processing Information
6 Throttle Sensor
7 Fuel Enrichment Solenoid

In my experience, anything but a 1 flashing indicates a problem circuit, if 33-44 flash this indicates a potential ecm failure..

[rodbolt17]

on the old 3.1L carbed motors I think code 10 and 34 were used for tilt signal recognition.
one was for a failure the other was for out of range.
as far as I remember code 34 was only used on the 3.1l carbed motors.

[boscoe99]

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