omc 6 cyl no water pumping out

A friend just got a 71 cobalt and we got it running today. we were hoping to see some water out the exhaust but there was nothing. there is no exhaust bellow on right now, so I was thinking we should have seen something. we were using a cut drum barrel plenty full and let it fun for about a minute. there is a temp gauge that never reached 130 degrees but that might be broken.so we shut it down and thought i would find out some info. is there a thermostat that might not let water cycle until it reaches operating temp? there is a little screen above the prop, that is the water pick-up right? is there a hose that connects to the motor from the outdrive? we were looking and all we could find was a small hose about 3/8 inch way up above the exhaust bellow i was thinking it was a vent for the lower unit. thanks for all the help.
Kurt

Re: omc 6 cyl no water pumping out

It would help to know what drive we are working with here.

The little hose may be the shift cable. Running with no water coming out the exhaust is expensive. The exhaust water is what cools the rubber connectors in the exhaust system. Too long (like 30 sec. or less) and you fry the rubber connectors from the inside and they will look good on the outside. Check them by squeezing them and see if they are fried. Also (if not fried) re-tighten all the clamps.

Thermostat could be stuck or broken, but there is a bypass to allow water in the exhaust to cool the couplers. Depending on which thermo housing you have, and there are several styles, it could have been put back together wrong from previous repair attempt.

Re: omc 6 cyl no water pumping out

If you have a 71 OMC then it has to be a stringer. Stringer drive CANNOT suck water because their impellers are too high. You really need to put a radiator flush adapter into the line that runs from the intermediate housing The water MUST come from a point above the impeller or it cannot push water the water into the engine. A lot of people install a flush adapters to the trunnion covers on either side of the drive instead of a radiator flush adapter.

Re: omc 6 cyl no water pumping out

sorry i am nautically illiterate, haha!! but i am unsure of what you are referring to with the intermediate housing and the trunion cover. how high is the impeller?
thanks.
Kurt

Re: omc 6 cyl no water pumping out

Take a look at the picture below. Circle number 1 is the approximate location of the impeller and circle number 2 is a trunnion cover.

The low end looks different on this model because it is a mechanical shift unit. Please ignore the flush muffs they do not work on stringers. The last owner placed them on there.

Re: omc 6 cyl no water pumping out

I think he is just going to take the boat to the marina and have them do everything. he is in a hurry to get his boat running. I think I will still be installing a flush adapter in it and I did get the motor to run for him. that will save him some money. thanks for all the help.