D4 6U water problem any ideas?

Could be you fixed the problem. On the u series Cats always check the pre- combustion chambers first.They are easier to unscrew when the head is still bolted down not moving around.The chamber will rust wholes some time or the cooper gasket will go bad.Generally the Cat heads are really tough.Not that there is anything on a 60 year old machine that cannot fail.
Have D6 of the same vintage had temperature gauge that was failing(NEVER READ OVER 190 IN A PAN OF BOILING WATER),got very hot and push water out after this.Pulled head gasket ?? no cracks ,had it surfaced put it back on same problem.Pre-combustion chamber fixed it.
In some conditions it is very hard to keep radiator clean so watch it closely.Hope all goes well with your project.
Ray

I would delay pulling PC chambers until you know you need to. Can be unlucky and pull the threads out of the head as they come out.

If they need to come out, then get out your breaker bar and go for it, but make sure first.

Hi ccjersey,
is there a best approach for assessing the precombustion chambers? I can see if they're really shot the water leakage would be obvious but what if they're close but not quite leaking? It'd be a pain to pull the head (as I need to replace a liner), notice that they aren't leaking, refit the head and then a couple of months down the road have one of them start leaking - I'm guessing though there's no easy way?
By the way, on another thread I mentioned my D23J ring gear was straight, not helical. I was wrong (duh - not the first time, sure won't be the last : ). I got mixed up because I was looking at the pony starter at the same time. Apologies for any head-scratching that went on.
Cheers,
Neil.

so i started the old D4 again and once again its back to spitting water out the over flow tube. Tighting the fan belt didnt fix the problem bummer. I decided i want this problem to be fixed. I pulled the top water pipe off and took out the water regulator, to find the part # 6f9467 is this the right one? my parts book says its part # 8f8817 which one should i go with. but i really dont think that this is my problem. When i bought the D4 the pony motor was bad so i took it off and closed off the water ports and put electric start on it, i was thinking that i messed up the flow of water but then remembered it was spitting water out before all of this... So anyone have any suggestions?

my serial # 6U8927sp
i took a pic. of of the water reulator that came out of it. The pic of the seat is i know not orignal but i wanted something different so i took the wood and cut out new i took the arm rest and maid them thicker and turn them upright and then my mom maid the rest and did the custom cat letters

Did you drop that regulator into a pan of hot water and see if it would open? At what temp? Always check the easy stuff first. Sometimes you get lucky.

Love the seat.
Nice job on that.
Chris

You say it pushes out water INSTANTLY after starting? to me this = not the thermostat but precom chambers or head/gasket problems.

You say it pushes out water INSTANTLY after starting? to me this = not the thermostat but precom chambers or head/gasket problems.