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318 cooling problems

A

Alotis

New member
Gentlemen - I need your help

My 318 has some cooling problems. The Exhaust manifolds become too hot to touch which to me is caused by not enough water flowing through the Manifolds.

I have removed the thermostat and have installed 2 new Impellars. Old Impellars were soft and intact - no debris - The Water Pump pully when facing the Engine turns clockwise. With the pump apart and looking towards the pully the vanes turn counter Clockwise. The other impellar was installed in the same rotation. The engine was started and water is coming out of the rear Exhaust This did not work.

All hoses and clamps were inspected - some replaced. I tried as best as I could tp prime the cooloing system. This did not work. The manifolds get way too hot - the hoses to the Oil Cooler were hot - the hoses from the Water Pump to the exhust manifold are aslo hot.

Here is the weird part. The water should flow from the Water Pump through the Water Pump Housing across via a hose to the Block I forgot to tighten the clamp on the pump housing and when the engine was started water leak out the clamp. To make a long story short it was not water coming from water pump but water from the Block. ??????

I have done someting wrong but I dont know what. - your comments will be appreciated
 
What does the water temp gauge read? Raw water I assume? Take the Hoses off your Oil Cooler and make sure that is free of debris. The holes in there are about the size of a pencil and clog easily. I check/clean mine about every 2 weeks. I don't think that is your only problem but if it is similar to mine the water does need to make it through there to make it second pocket of the water pump. On the bottom side of the my raw water pump there is an IN and an OUT. The specs in my manual want me to run the hoses opposite of the In and OUT ports. But when we run them Raw water into the in and watet from the oil cooler into the second pocket, it runs much coolers. Hope this helps. Others will know much more.

They will tell you to make sure you have no air leaks before the pump( it doesn't take much). And with a dual impeller pump you probably want it to be air tight throughout.
 
Hello

I believe that I left out a couple of important facts

This is a Raw Water cooled port engine. The pump is installed with the Draining screws on the housing pointed towards the outside of the boat. Pump pulley turns CW - Impellars turn CCW (inside)

Upon startup with the boat in the water the water pump quickly started to smoke and was to hot to touch. Open the waterpump and found the Impellars to be intact and soft - no debris. I thought that this was due to the cooling system not properly primed. Replaced the impellars - otherwise the Pump seem ok

Regards
 
It sounds like the impellers are placed into the pump with the wrong fin orientation. If the pump pulley turns CW, then the impellers also turn CW, but the impeller fins get dragged along the inner surface of the pump housing and therefore point in the CCW direction.

If your turns CW, then your impellars should look like this:


impeller%20001.jpg

-JJ
 
capnlazy said:
Sounds like the pump is upside down, blowing air instead of sucking water.
Click to expand...

Even if you mount a pump upside down, the direction of rotation is still the same. It wouldn't "blow air". The only way it would "blow air" is if you mounted it backwards which is impossible since the pulley would be on the back side of the pump.

-JJ
 
Did you check the exhaust hoses ?I had one collapse internally this will give high temps.
Checking the impellers is a good idea. Idid mine and found I installed backwards!
Good Luck
Bob
 
Pump is upside down... done it my self a few times..take it off flip it...close the sea cock...pour some dish soap into the outlets.spin the pump by hand to move the soap around..re-install belt..prime..open sea cock & start..look for bubbles at the exhuast
 
If you installed pump upside down you would definitely affect its efficiency, but it wouldnt blow air. As long as the impellar is installed in the correct orientation and turning turning the right way, then your picking up some amount of water.

-JJ
 
If the pump was upside down it will not pump water at all. These pumps have a dedicated suction and discharge. There are no expeptions to the way water will flow when rotation remains the same. Ive done it before and know for a fact. The water goes the long way around the pump not directly across the hose fittings.
 
I am back. Been away on a Hoilday.

I went back to the boat determined to check all the hoses for condition and installation (ends and clamps)

Still this made no difference. Ok lets try backflushing. To my amazement water began leaking from Oil Cooler hose attached to the Water Pump. Cut the bad end of the hose off and reattached it to the pump.
I looked at that this hose numerous times and did not see that spilt.

The engine nows runs , water is pumping out the rear exhaust and the Exhaust Manifolds are now not too hot to touch
.
However both the manifolds run very hot and I have not put the thermostat back in. The block and cylinders head are both cool Water from the thermostat to the bottom of the Exh Manifold is hot and from the other end of the manifold to the Oil Cooler is very hot.

Even though there is water being pumped out the rear exhaust it is not alot.

The only thing that I can think of is that there still a leak at the Oil cooler hose to the Water Pump. This is a re enforced wire hose and the gear clamp cannot seal the connection.??? I am going to replace the hose.

As both manifolds are affected I believe that there is not enough water running thru the cooling system

Thanks for your replies
 
If the pump was installed upside down it would be pulling water thru the block (if that is even possible) and discharging it thru the water pickup. The water pump doesn't know that it is upside down and then decide to change input and output ports.
 
I am having some cooling issues on my RH 318L. I also have a LH 318L. Are the water pumps different for a Right Hand Drive vs Left Hand Drive engine?
We have managed to mix up the pumps and are trying to get them figure out and determine which way they mount. They both have 2 screws in the housing on the same side that the back two outlets are stamped "Hot--Out". I can attach a picture to the next post if that would help. We have replaced a shot impeller and are in process of checking cooling system for debris from the impeller--I am thinking the oil cooler is the most likely location for the debris if not the thermostat. Engine exhaust manifold/pipe have been running too hot so we have shut down immediately. We also discovered both exhaust manifolds are cracked and am in process of trading them out with the backup engine and will see about fixing the cracked ones with JB weld etc. any information on identifying which pump is which or how to mount it would be very helpful

jeffrey
 
In mine the stamps on the port side motor were irreverent. I tried hooking it up according to them and had the water hitting the engine first rather than the exhaust manifolds. The service Manuel shows this as incorrect. You have to remember both pockets are just pumps and it matters where the water is piped more than what the stamps say.
 
Pete,
im having the same problem with my waterpump getting hot. If the waterpump is upside down the molded hoses will not reach. im sorry for beating a dead horse but this is driving me NUTS.
Thanks
Scott
 
yes, check the oil cooler for debris if an impeller blew up. We went through 3 sets of impellers, repaired two exhaust manifolds, 4-5 v belt fall offs, replaced the water intake hose from the bottom of the boat with a wire reinforced hose and got the pump mounted with the ports on the starboard side on a right hand turning motor and now we have stable cooling! good news is I can take off that pump and replace impellers and install in no time at all.
 
I suspect you have an air leak before the raw water pump. It doesn't take much to cause all kinds of hell!

Jeff
 
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