Overheat..but why?

[crash1big]

I have an 05 250 xs that has been running around 14 psi water pressure WOT since I bought it. The other day it went to 19-21 psi wot. ?? I figured something let loose. The next few times I went out it was the same 19-21. I thought I might raise the motor seeing as I am 1 in. above the pad with a torque master. However the last time I went out the water temps were in the low 50's; so i took my time idling along for a bit before I got on plane. I eased it to about half throttle for a bit then to wot for about 3 minutes and the over heat alarm went off. I shut it down and waited about 20 minutes. On start up it had good water pressure (about 6 psi at idle) But it kind of moved around a bit as I got on plane. I went back and pulled out. Any Ideas?

[bilco]

When is the last time you changed thr impellor?

[Astro-T]

never mind... I reread your WHOLE post this time!

[prepsdk]

I would check the poppet valve, sounds like it could be stuck.

[EuropeanAM]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by crash1big &raquo;</td></tr><tr><td class="quote">I have an 05 250 xs that has been running around 14 psi water pressure WOT since I bought it. The other day it went to 19-21 psi wot. ?? I figured something let loose. The next few times I went out it was the same 19-21. I thought I might raise the motor seeing as I am 1 in. above the pad with a torque master. However the last time I went out the water temps were in the low 50's; so i took my time idling along for a bit before I got on plane. I eased it to about half throttle for a bit then to wot for about 3 minutes and the over heat alarm went off. I shut it down and waited about 20 minutes. On start up it had good water pressure (about 6 psi at idle) But it kind of moved around a bit as I got on plane. I went back and pulled out. Any Ideas? </td></tr></table>

When chasing down cooling system problems.... ALWAYS, ALWAYS start at the SOURCE: The Water Pump.

Kit without housing: 43026Q06
Kit WITH housing: 817275A08

You may have debris (such as wood) stuck in the gearcase between the LOW WATER PICKUPS and the water pump plate. It's necessary to remove the SHIFT SHAFT SEAL/BUSHING PLATE, and the COMPLETE water pump AND lower plate in order to accurately determine if this is the case.

Ensure telltale stream is CLEAR after pump replacement (telltale is the outlet for air compressor cooling circuit- if plugged, it will cause the COMPRESSOR to overheat).

If, and ONLY if water pressure or overheating problems occur AFTER water pump replacement.... it is then appropriate to move on to other potential cuases (thermostats, poppet valve, powerhead/adapter plate gaskets, etc).

[crash1big]

Thanks fellas. The impeller is about a year old. Guess I'll pull the LU and start looking around. I'll try to give an update.

[crash1big]

So I pulled the LU and inspected the impeller and what not. All looks good. No blockages. Pulled the thermostats and no blockages. Inspected the poppet and no blockages. I tested the thermostats and they both opened okay, however; one stuck open at 160 and wouldn't shut. My engine has 120's and I have a new set of 130's. Would there be a disadvantage or advantage to using the warmer thermostats? This engine seems to have always run a bit rich as there is always a significant amount of carbon at the hub.

I did find that the water pressure line was kinked a bit. Might explain why the w/p was bouncing around. Any other suggestions? Thanks!

[crash1big]

Oh lookie what I found! Wonder where the rest of that gasket went? [img][/img]

[EuropeanAM]

That'll cause problems, for sure.

ALWAYS replace the gaskets when doing the water pump.

In regards to your thermostats.... 130 degree thermostats (2 of them) are the only available replacement part for this engine now.

Make sure you replace BOTH thermostats with 130's at the SAME TIME, however.