Water circulation issues
 

When I got my boat it had a Gen IV block that had a cam in it with 9 worn lobes on it. I was lucky enough to get a 454 Volvo Penta motor with fresh water cooling and a sepentine drive system. The Volvo motor was rebuilt and made a 468 with forged pistons and scat rods along with a Bob Madera custom hydraulic roller cam. The motor was dynoed at 451 hp and 511 ft/lbs torque. We put the motor in the boat this weekend to crank it and get it ready for the summer. When we started it, it never pumped water through the exhaust. We did remove the hose that hooks up to the drive assembly and force water through the whole system and water came out the exhaust but when we tried to run the motor on the muffs it wouldn't pump the water. The raw water pump was rebuilt with new bearings, seal and impeller and the exhaust is a dry Stellings system with everything going through the freshwater cooling system. We took the pump back apart and the consensus was that the impeller vanes were to pliable and collapsing when trying to pump the water. When comparing the impeller vanes stiffness to a Bravo sea pump impeller the volvo impeller was much easier to get into the housing and move the vanes themselves. My question is has anyone had this issue before and how did you correct it? Does the pliability of the impeller sound like it could be the issue? I am going to try and find another impeller and see if the vanes are more stiff than what I have. If they aren't I'm at a loss on how to fix it without spending $450 on a new Volvo Penta water pump. Any help would be geatly appreciated.

make sure the hoses from the drive to the raw water pump to the heat exchanger are hooked up right

We double and triple checked this and all hoses were routed correctly. When we pulled the hose off the back of the drive and put the water hose directly to this hose and sealed it off we were able to use only the water hose pressure to fill the system and have water come out of the exhaust. If we had the hoses hooked up wrong I don't think the water would have come out of the exhaust like it did.

your water pressure could force water through the pump even if the hoses were hooked up backwards have seen this happen.

Fixx
 

the volvo impellers are soft and will be easy to move..remove the hoses @ the rear of the engine and have a friend start the engine and put your hand over the suction hose to feel if it is sucking,you may have the hoses at the sea pump reversed..also check the cooler for old impeller parts..like stated the hose water will force past the impeller...

also check the seal between the drive and the gimbal,,if the seal were to slip or leak it will blow the water out of the prop also on the hose..

With a new engine I always start with hose that hooks the seapump to transom disconnected at the transom. Shove the garden hose down this hose. Water will be flowing out the intake hose profusely until you crank the engine. When then engine starts all overflowing should stop. If it is overflowing worse, the intake hose is plumbed to the output side of the pump

If water is not overflowing, your problem is between the drive pickup and transom mount where the seapump hose connects.

When we first started it and it wasn't pumping water we double checked the hoses on the pump and they were backwards. We changed them around and filled the hose from the drive to the pump with water and started it again. Still no water coming out. The water comes from the drive to the water pump, out the water pump to the oil and power steering cooler and then to the heat exchanger. Once through the heat exchanger it splits and goes to each header. We pull the hose off that comes from the pump to the heat exchanger and it wouldn't pump the water that was already in the line out. I have never heard about the seal at the drive being an issue. Fixx, are you referring to the seal between the transom assembly and the little plastic elbow that the hose from the pump goes on? We worked on this for a couple of hours trying different things, switching hoses around, and nothing worked. Thats why we figured it had to be the impeller on the pump. There was discoloration in the pump from old water residue and the impeller never looked like it touched this area. We did run the motor with the hose shoved down the pump hose and basically the house water pressure filled the system and we ran the motor like this. Any suggestions on what else can be done to fix this? What type of pumps can I go with to work with the serpentine system?

Like I said in part 2 of my description, if flow is fine with the garden hose shoved down the input hose to the seapump, your problem is between the outdrive pickup and where the input hose mounts on the transom. The rubber hose in the bellhousing could be blocked/twisted, there could be suction leaks in hose connections or your oring between upper and lower could be missing. I ran the type pump you are using on a volvo for years and it was bulletproof. Better than the merc impeller.

After thinking about it some more and talking to some more people I am thinking its a air issue also. I am going to put the pump back on tonight and crank it and see if I have suction on the hose on the outdrive. If I do then its getting air somewhere in the drive. Then I will pull the drive off and make sure all the o-rings are in place. Then I will put it in the water and see if it pumps then.

Run water back through the hose going to the outdrive. Make sure water is only coming out the intake and no where else. It should flow through there almost w/o restriction.