1968 merc wont pump water

[67starcraft]

hey guys, new to the show here but already i have a question. i have a 1968 merc 60 (6hp) that i just bought but it wont pump water. i replaced the impeller couse it was toast abd blwe out the lines but i still cant get it to pump. the only thing i can think of is the copper tube inside the mid section isnt sealing against the impeller housing or something like that. anyone got any ideas?

 

[Fuzzytbay]

Re: 1968 merc wont pump water

A couple of thoughts, first, did you put the impeller in correctly, ie so it pumps water. Its possible to put it in so the veins are not pushing the water up the tube. Second, its quite common for "peice's" of the old impeller to have migrated up the tube and are now blocking the water. When you blew out the lines, did you check for air at the pee hole? Third when you ran the motor, was it on muffs or in the water? My thought would be, if you ran it in the water, it might be pumping, yet the pee hole water circuit is blocked. If thats the case, you might have to clean that out by pushing something into it.

 

[latin monkey]

Re: 1968 merc wont pump water

make sure water tube is clear. with lower unit off look up into midsection with a flashlight and you will see where the tube goes in the bottom of water jacket housing under the powerhead. make sure water tube is in there first then install lower unit and make sure water tube goes in water pump housing correctly. if it still wont circulate water then there is probably obstruction or corrosion in water jackets in powerhead or maybe thermostat and poppet valve if you have them on your motor. also check water hoses and fittings and make sure they arent obstructed. hope this helps

 

[67starcraft]

Re: 1968 merc wont pump water

i let it sit for few mins and started it up again and it did pump water but it was intermittent. it would flow good for a couple seconds then stop and the water coming out of the peehole was relay hot to the touch. then it stopped and turned to a little trickle. ive never had a boat b-4 so im new to all this

 

[karatejoe]

Re: 1968 merc wont pump water

when the impellar is toast it leaves pieces of hard rubber in the case and tube. I spent 45 minutes trying to get the pieces out of my alpha 1 drive. That was harder than replaceing the impellar. I would tear it down again and look really close with a good light.

 

[SC1650]

Re: 1968 merc wont pump water

A couple of thoughts, first, did you put the impeller in correctly, ie so it pumps water. Its possible to put it in so the veins are not pushing the water up the tube. Second, its quite common for "peice's" of the old impeller to have migrated up the tube and are now blocking the water. When you blew out the lines, did you check for air at the pee hole? Third when you ran the motor, was it on muffs or in the water? My thought would be, if you ran it in the water, it might be pumping, yet the pee hole water circuit is blocked. If thats the case, you might have to clean that out by pushing something into it.

I have a question. Why is there a right way and a wrong way to put the impeller in???? Remember that you can go forward or backward with these motors. They should pump water no matter which direction you go. As a matter of fact, most anglers in my area prefer to troll backwards as it slows down the boat more than forward movement and the water pumps consistently all the time.

Steve

 

[nathanhooper]

Re: 1968 merc wont pump water

I have a question. Why is there a right way and a wrong way to put the impeller in???? Remember that you can go forward or backward with these motors. They should pump water no matter which direction you go. As a matter of fact, most anglers in my area prefer to troll backwards as it slows down the boat more than forward movement and the water pumps consistently all the time.

Steve

The drive shaft allways turns in the same direction, forward or reverse. Only the prop shaft changes direction. The impeller is on the drive shaft.

 

[SC1650]

Re: 1968 merc wont pump water

The drive shaft allways turns in the same direction, forward or reverse. Only the prop shaft changes direction. The impeller is on the drive shaft.

OK. Now which way should the impeller be installed??? I used a wire tie to pull the fins together and I believe that as I looked at it the blades bent to the left side of the motor as you look at from the rear. If I installed it incorrectly will I get any water to pump at all when I start it??

 

[Fuzzytbay]

Re: 1968 merc wont pump water

I have a question. Why is there a right way and a wrong way to put the impeller in???? Remember that you can go forward or backward with these motors. They should pump water no matter which direction you go. As a matter of fact, most anglers in my area prefer to troll backwards as it slows down the boat more than forward movement and the water pumps consistently all the time.

Steve

The fin's or veins onthe impeller do the pumping on a water pump, if the veins do not grab the water and "throw the water up" the water in take tube, it will not pump water with any pressure. There ARE two ways the impeller can go in, one with the fins pushing the water, and one where it the water slides off them.
So you cannot put the impeller in upside down, it matters not which side goes in to the back of the water pump houseing, but the manner in which the fins are placed in the housing, can be done backwards. Hope that helps, clear up, how a water pump impeller can be installed "backwards".