old merc water pump

[MH7142]

i have old merc 400 thunder bolt 1960-61 i was wondering if anybody could tell me how to tell if water pump is working i put a 55 gallon drumfilled it with water i run motor for about 5 minutes and it didnt get hot when i give it throttle it started bubbling where does water come out the guy i bought it from said pump was bad how can i tell

 

[JB]

Re: old merc water pump

Moving to Mercs

 

[Darryl34]

Re: old merc water pump

If it's anything like the 70's style,the water comes out with the exhaust through the prop.Their should also be a hole in the lower cowl rear right side with water comeing out from the head for cooling.If you've got ear moffs,use them,then you will be able to tell a little better how much circulation you are getting.

 

[Chinewalker]

Re: old merc water pump

In the belly pan (lower cowling) on the port side of the motor, near where the cowling meets the exhaust housing (mid-section) there should be a pin-hole water relief outlet. Get a piece of wire and clean that out.<br /><br />That motor will also spritz a mist out the exhaust relief nub on the rear of the exhaust housing.<br /><br />95% of the water goes out the exhaust in the lower unit, under the anti-ventilation plate.<br /><br />If you're unsure about anything cooling related, put in a new impeller - they're cheap insurance. Might have to go to oldmercs.com to find a manual for yours.<br /><br />- Scott

 

[Virago85]

Re: old merc water pump

I have a 77 175 and mine will not put water out of the pee hole unless I am under throttle call mer and the said that is normall for the biger mercs it runs about 130 thru no wake and about 100 under throtle