Help, trying to diagnose a problem....

[Mermaid Michelle]

Goodmorning, we have a 2006 Yamaha outboard motors, 2, 250's.

Morning. I have twin 2004 250 Yamaha outboards. The starboard engine was over heating. We replaced the impeller housing and it fixed it. The issue now is when the engine is warmed up the throttle control locks up and rpm s increase and am unable to return to neutral unless I shut the motor off. Thenit acts normally with the motor off. We replaced the cable. Lubed throttle and choke.

[rodbolt17]

can we get a model number?
all I can tell you about them now is most likely the paint code will be 8D.

[boscoe99]

Second on the need for model identities.

You start off by saying 2006 250's. With 250's being two strokes.

Then you say twin 2004 250 outboard motors.

I suspect they are really F250's but beyond that, and agreement with the colour, I have not a clue as to what you have.

Was the motor working just fine except for the over temperature, and all you did was to remove and replace the lower unit, and then the shift problem began? And since you say it is happening when the motor is warmed up are we to assume that the shift works just fine when the engine is cold?

[Mermaid Michelle]

still trying to figure it our

2004 F225 Twin outboards, yes, they are white


Was the motor working just fine except for the over temperature, and all you did was to remove and replace the lower unit, and then the shift problem began? And since you say it is happening when the motor is warmed up are we to assume that the shift works just fine when the engine is cold?

Yes shift works fine when getting started, it's happening after engine is warmed up, engine not overheating, it just get stucks and we can't pull back to neutral unless we turn the key off and have to start the motor back up and it starts reving up by itself, like theirs a ghost..
Still looking for the exact model # for the engines.

[rodbolt17]

we really gotta have them thar numbuurs.
the first of the US market F250's was 2005 and Yamaha never painted anything since the 80's in white.

[rodbolt17]

I can tell you that all late model large Yamaha outboards use a shift cut switch of one design or the other.
you sure they are not F225 motors?

[boscoe99]

Now they are F225's and not F250's?

"2004 F225 Twin outboards, yes, they are white"

Early F225's had a recall for throttle linkage that prevents the motor from idling down as it should, in which case it can be difficult of impossible to shift from in gear to out of gear.

Did your motors have the recall modification done? Maybe they need it again, or the linkage to be inspected.

[Mermaid Michelle]

Found the serial #'s off the F225s

F225TXRB
69JX1001328
Q

We called the Yamaha and had them look in their computer, he said that the recall has been done.

Anyone have any idea about whether there is a TPS switch too?

Thank you so much, Michelle

[boscoe99]

F225TXRB
69JX1001328
Q

We called the Yamaha and had them look in their computer, he said that the recall has been done.

Anyone have any idea about whether there is a TPS switch too?

Thank you so much, Michelle

There is no TPS switch. The throttle position sensor (TPS) is a device (potentiometer) that simply tells the brains of the motor in which position the throttles valves happen to be.

Let us assume that with the engine in neutral gear that the throttles are opening and closing smoothly and correctly. This will eliminate the possibility that a defective linkage is causing the problem. We also need to assume that no codes are being set by the motor which can result in a fast idle.

Have you tried disconnecting the control cable attach fitting at the motor to ensure that it is the motor that is causing the problem and not something control cable related?

With the motor running and in gear, when you retard the throttle so that the motor is in gear but running at its lowest RPM, what is that RPM? It should be 650 RPM plus or minus 50. Try disconnecting the control cable and see if it idles down or remains at a fast idle?

Your motor also has a SIS (shift interrupt switch) that misfires some cylinders when the motor is being shifted from in gear to out of gear to help the shift process. But if the motor is not idling down to 650 plus or minus RPM when just into forward gear I am guessing that you have a different issue. The switch can easily be tested since it is either open or it is closed.

When was the last time all of the throttle linkages were inspected, cleaned and lubricated? That is a Rube Go-lDberg motor when it comes to linkages.

[rodbolt17]

the TXRB indicates its an 03.

they are first gen v6.
they have a tps.
a shift cut switch.
a shift position switch.
an ISC valve.
a map sensor.
a barometric sensor.
an intake air sensor.
a coolent temp sensor.

no codes for the ISC, no real tests other than a static or running that wont show much.

there were two updates for the throttle links and one update for an overcharge condition.

try to obtain and post a running download.

[TownsendsFJR1300]

As all you did was a WP housing replacement, I tend to think perhaps your shifter spline at the LU may have moved upon re-installation.

Just to cover your butt, you might consider pulling the LU, making sure its in neutral and the throttle cable (alignment marks under the cowl) are in neutral and re-assemble.

It certainly won't take long (if your out of the water).

Just my 2cts.