Tech Answer on 250TXR 2007 4 Stroke

[Capt.Terry]

Question; Is there a Poppit valve on these motors?

I have been getting mixed answers and can not locate one if it is there!

also can a technician id these two bolts and what they are for ?
engine stern 2 large bolts .JPG
their location is lower stern of engine between port and starboard heads

Thank you

[DennisG01]

I can't directly answer either of your questions, but here's an easy, self-help way... At the top of this page is a link to Yamaha parts. Click on that and then select your model and you can look at any parts diagram (with descriptions) that you want.

[boscoe99]

Yes, that model employs a pressure control valve. You have to remove a plastic access cover at the rear of the motor to get to it. See diagram below.

The two bolts that you refer to are plugs. They can be removed to gain access to the engine exhaust. Say for example someone wants to install an O2 sensor or an exhaust gas temperature sensor. That is where those devices would be used.

[Capt.Terry]

boscoe99
Thank you for this information, I will be looking at this hopefully tomorrow
Do you know the size of the socket needed ?
I am trouble shooting an issue that seems to come up from my readings on these 250 Yamaha's this is a 2007 and a very clean engine. Running the boat *****ing, etc., engine performs well oil, water temp. all stays about 2/3rds on gauge. Issue happens when I happen to back down for a period or sit at idle the high temp alarm sounds. the gauges do not show temp rising? If I shut her down I can start her up and alarm is gone unless I go back to idle and or go into reverse if temp was high alarm should not go away when restarting?
I just removed both Thermostats an replaced them and I also removed and tested the temp sensors for a problem there but the old thermostats checked to both open at about 160 deg. and I checked the temp sensors and they were open and closed at approx 185 - 190 degrees, so they also seem to be OK.Thermostat & Temp Sensors 250HP 4 stroke Yamaha 2007.JPG
I am happy you showed there is a Poppit Valve because someone indicated there was none, so I was not sure where to check from here. But I will check that next tomorrow, when I replace the temp sensors. If you have any ideas for me to go check to figure this out it would be a great help. I am on an Island and not much help here but oneself.

[Capt.Terry]

I can't directly answer either of your questions, but here's an easy, self-help way... At the top of this page is a link to Yamaha parts. Click on that and then select your model and you can look at any parts diagram (with descriptions) that you want.

Thank you for the tip.

[fairdeal]

are you certain that your water pump is in good shape?

it seems often folks will say " it can't be my pump, I just replaced it"

it only takes a few minutes of running "dry" to melt the impeller or that plastic housing -

if there is reduced output, it may be ok at higher rpms

but not at idle when the pump is only turning 6- 700 rpm

[boscoe99]

Either the water pump being worn and needing to be replaced or the poppet valve being stuck open could result in low water pressure and thus over temperature at idle.

One trick to check for water pressure is to get a water pressure gauge from a Home Depot or similar store. Plumb it to the garden hose female fitting. See how much pressure that you have at various engine RPM's.

Have you removed the lower unit inlet screens and checked to ensure that all of the water passage ways to the pump impeller are free and clear? Check from both ends. From the top with the water pump plate removed and from the bottom with the screens removed.

With the lower unit removed tilt the motor to the full up position and using a bright light inspect the engine exhaust. What does it look like?

[Capt.Terry]

are you certain that your water pump is in good shape?

it seems often folks will say " it can't be my pump, I just replaced it"

it only takes a few minutes of running "dry" to melt the impeller or that plastic housing -

if there is reduced output, it may be ok at higher rpms

but not at idle when the pump is only turning 6- 700 rpm

I am going to double check the impeller one more time This was the first thing replaced, before I return back in water, I also got to check the poppit valve today it looks OK as far as I can tell and no corrosion or blockage any where?
it depresses and pops back actually it is spring loaded

[Capt.Terry]

Either the water pump being worn and needing to be replaced or the poppet valve being stuck open could result in low water pressure and thus over temperature at idle.

One trick to check for water pressure is to get a water pressure gauge from a Home Depot or similar store. Plumb it to the garden hose female fitting. See how much pressure that you have at various engine RPM's.

Have you removed the lower unit inlet screens and checked to ensure that all of the water passage ways to the pump impeller are free and clear? Check from both ends. From the top with the water pump plate removed and from the bottom with the screens removed.

With the lower unit removed tilt the motor to the full up position and using a bright light inspect the engine exhaust. What does it look like?

Yes to the screens being clear, poppit checked today looks ok no corrosion depresses and has no issue returning as it is spring tension.
When I recheck the impeller I'll check the Exhaust port.
Will only know when I get it back in the water. ??

[Capt.Terry]

Yes, that model employs a pressure control valve. You have to remove a plastic access cover at the rear of the motor to get to it. See diagram below.

The two bolts that you refer to are plugs. They can be removed to gain access to the engine exhaust. Say for example someone wants to install an O2 sensor or an exhaust gas temperature sensor. That is where those devices would be used.

Got to the Poppit Valve today removed it and it looks clean no corrosion and depresses and returns it is spring forced to close. its port was clean no corrosion so it went back in I do not have a replacement, so silicon-ed it up lubricated it as best one can and back in.? will have to wait until back in the water to see if any of the inspections and replaced thermostats do the trick?

[TownsendsFJR1300]

How old IS the WP impeller?

As noted above, with the low RPM's, it sounds like NOT enough water is being delivered at idle.

You mentioned you checked it, NOT replaced it.. The impeller will take a set over time, rubber get hard and not pump as well as a new one..

Purchase the entire WP kit. A bad seal / o-ring can loose pressure. Make sure the SS cup has NOT spun in the housing.

Also CLOSELY inspect and replace the WP housing if there is ANY doubt about it's condition.



.

[99yam40]

just a heads up, putting sillycone on may lead to it squeezing out into the water passage ,coming loose and going somewhere you do not want it to be plugging things up

[Capt.Terry]

How old IS the WP impeller?

As noted above, with the low RPM's, it sounds like NOT enough water is being delivered at idle.

You mentioned you checked it, NOT replaced it.. The impeller will take a set over time, rubber get hard and not pump as well as a new one..

Purchase the entire WP kit. A bad seal / o-ring can loose pressure. Make sure the SS cup has NOT spun in the housing.

Also CLOSELY inspect and replace the WP housing if there is ANY doubt about it's condition.




.

The Impeller replaced maybe 5 weeks now was first thing done, yes old one had issues but new one did not stop alarm at idle I also believe what you say motor not getting enough water on idle or backing down, but gauge does not indicate overheat all is OK there, only alarm is sounding which lead me to a sensor maybe being faulty or stuck ?hank you

[TownsendsFJR1300]

The Impeller replaced maybe 5 weeks now was first thing done, yes old one had issues but new one did not stop alarm at idle I also believe what you say motor not getting enough water on idle or backing down, but gauge does not indicate overheat all is OK there, only alarm is sounding which lead me to a sensor maybe being faulty or stuck ?hank you

Who did the pump and I gather they did NOT do the entire kit?

IMO, I'd be back in there and do an entire kit.

*Most shops will NOT do just an impeller- for the reason that should there STILL be an issue, they get to do a "do over". A slightly warped/overheated housing WILL cause pumping issues. (Been documented many times here..)

I ask in that the drive shaft HAS to be turned clockwise when installing the cup.

Good luck..

99YAM, I believe he used silicone LUBRICANT, not sealer..



.

[Capt.Terry]

Who did the pump and I gather they did NOT do the entire kit?

IMO, I'd be back in there and do an entire kit.

*Most shops will NOT do just an impeller- for the reason that should there STILL be an issue, they get to do a "do over". A slightly warped/overheated housing WILL cause pumping issues. (Been documented many times here..)

I ask in that the drive shaft HAS to be turned clockwise when installing the cup.

Good luck..

99YAM, I believe he used silicone LUBRICANT, not sealer..



.

Well I did the impeller replacement. Previous owner before he sold it said he just did the impeller and watched the mechanic put it in. yeah right, I should have know better. So with the issue and also a questionable pissing weakness in other words the pissing isn't force full like on some engines and not having a twin could not compare the pissing force, but it was pissing. So we pulled the impeller out it, was as if it was in there for a few years had wear was hardened a little and was out of shape and one blade tip was cracked. So we thought well this is the problem. Your right ! I didn't do the complete rebuild or full housing I only had an extra impeller on hand. I have the complete pump kit now so its back to taking it apart again and doing it all, you may be right it could be warped we checked it and it really look OK it was S/S, plastic housing out side. But I did not know of warping or to look for that! Now, I have gaskets, new impeller, housing, seals, o rings, and a s/s plate? to replace. If it was warped where would it show, would it be obvious ? I 'll now be able to compare the new to the old and see!
nothing more I can do, oh is there a trick to re assembling the lower unit once pump is installed to make sure the shift is aligned correctly ? when securing the lower unit back on?