97 225 SWSII will not idle below 1200 RPMs

[cousinabe]

I have twin 1997 Yamaha 225 Salt Water Series II engines. One of the engines will not idle below 1200rpms.<br /><br />After changing the plugs and commisioning the boat, one engine will not idle below 1200 rpms.<br /><br />When I first start them, they normally stay at 1200 and come down to about 800rpm once warmed up.<br /><br />I stabilize the fuel and top off the tanks prior to winter storage. In the spring I change the plugs and gap them to .35 as well.<br /><br />I did turn the idle set screw down, but that only got it to 1000rpms and does not seem the the correct fix.<br />I looked for a vacuum leak and did not find one.<br />The engines have 400 hours on them.<br /><br />Any thoughts?<br />How do the engines come down in idle once warmed?

 

[cousinabe]

Re: 97 225 SWSII will not idle below 1200 RPMs

1997 Yamaha 225 SWS-II<br />Model L225TXRV and S225TXRV<br />Serial: 62KUL 100332 and 62JUL 100933.

 

[rodbolt]

Re: 97 225 SWSII will not idle below 1200 RPMs

check the t-stats, the motor ,if you will check it, is locked at 7* BTDC or so.<br />a winky blinky will most likly show a code 33.<br /> its also possible that some one dissconected the knock sensor. if the thermosensor,and its possible its failed or dissconnected, does not tell the ECU the engine is at operating temp the engine stays in warm up mode, open loop.<br />but by playing with the idle screw you will now have to use the test harness and a DVM to reset the TPS voltage once you get the problem solved.<br />winky blinky cost 70 bucks or so, the O2 sensor harness and TPS harness about 25 dollars.<br /> well worth the money if ya wanna be a DIYSR with those motors.<br />without them your sunk. the tune-up spec guide is like 5 bucks and has all the codes in it.

 

[cousinabe]

Re: 97 225 SWSII will not idle below 1200 RPMs

cool, thanks.<br />where could i purchase that diagnostics equipt?<br /><br />sounds like it could be the themostats. they have never been changed and the boat is used in salt water. i will replace them.

 

[cousinabe]

Re: 97 225 SWSII will not idle below 1200 RPMs

 

[rodbolt]

Re: 97 225 SWSII will not idle below 1200 RPMs

any yamaha dealer can sell you the test equipment. you will find corrective maint is always more expensive than preventative maint.

 

[cousinabe]

Re: 97 225 SWSII will not idle below 1200 RPMs

after replacing the t-stats, would anything need to be reset re:ECU codes?

 

[rodbolt]

Re: 97 225 SWSII will not idle below 1200 RPMs

only the link and sync and TPS voltages caused ya messed with it.<br />however its all in your service manual.

 

[cousinabe]

Re: 97 225 SWSII will not idle below 1200 RPMs

replacing the t-stats did the trick.<br />thanks for your help rodbolt! It's always good to get the correct feedback from a knowledgable source.<br /><br />thanks again

 

[cousinabe]

Re: 97 225 SWSII will not idle below 1200 RPMs

am i missing something?
why would the TPS need to be reset after mucking with the idle set screw?

The manual says to set the TPS with the idle set screw turned out and valves fully closed. The TPS should read .50 - .52v.
After the idle set screw is brought up to 730rpm, the TPS now reads .62v.

 

[rodbolt]

Re: 97 225 SWSII will not idle below 1200 RPMs

lets get on the same page
you have an EFI motor.
that means the ECU controls the idle speed based on various sensor inputs by adjusting,on OX66, the fuel injection duration and the ign timing.
there are NO idle speed screws thats why there are holes in the throttle shutters.
if you adjust the shutter screw you also change the TPS voltage.
if the ECU sees a sensor failure,except O2, then it will lock the ign timing at 7*BTDC and engine idle speed increases.
in your case the ECU never saw the engine warm up so it stayed locked in base timing for cold start.
as long as you followed the manul to reset the idle TPS voltage your good to go.
but always remember if EFI idles fast or slow something is broke dont mess with a screw fix the motor.
with an O2 sensor failure fuel is fixed rich at low speed and lean above 4000 RPM,same if its contminated.
the ECU isnt very smart but it will react to an input whether its correct or not.

 

[cousinabe]

Re: 97 225 SWSII will not idle below 1200 RPMs

i do appreciate the help and i want to make sure we are on the same page.
I have a 1997 225 S225TXRV and LIT-18616-01-61 Service Manual.
pg 4-16 goes through the throttle valve synch. I adjusted accordingly.
pg 8-23 goes through the TPS checks and adjustments. I adjusted to .5v with throttle valves fully closed, linkage disconnected and throttle stop screw backed out.
pg 3-3 goes through idle speed adjustment. Turn the throttle stop screw in or out until the specified idle speed is obtained 730 +-30.

Are you saying that i do not have to adjust the idle speed using this screw?
My motor is idling at 500-600 rpm without using the set screw. TPS is at .5v.
Is this the correct setting or should i turn the screw to get 730 and higher tps voltage?

I get no codes with the winky blinky.
Thanks for your help.

 

[rodbolt]

Re: 97 225 SWSII will not idle below 1200 RPMs

as long as you have the manual follow it. however once set if the idle speed ever changes now you know its broke, fix it, not adjust the screw
what I am saying is that with EFI once the idle speed is set using the correct service procedure it should NEVER change again. if it does something broke.