converting to merc raw water type pump FINAL REPORT AND PICS WITH INSTRUCTIONS

[Bt Doctur]

For some reason always the seal start leaking and spraying water so after #3 crank mounted pumps I`m changing it to a engine mounted merc type using the Bravo impeller.A work in progress so check back for the final list,and ho to`s.. So far we removed the volvo type pump and pully. The volvo balancer has a snout so the merc pully had to be relieved a bit to fit the snout,.3 fine thread bolts and its mounted. The raw water pump bracket had to be relieved a bit due to the plastic timing chain cover .
Original belt for alt is unchanged.

Belt alignment is good and a 1/2 x 30.5 inch belt installed.You install the lower bolt first, then the belt, then the upper bolt. Push pump away from the balancer to snug belt. "Snug" meaning there is a 1/2 inch deflection of the belt midpoint., More than enough belt tension.

The power steering unit needs a bit of a mod to have it fit correctly 1 -3/4 spacers (3) machined from solid stock to space out the power steering pump to correctly fit the outermost pully groove of the merc engine pully To be able to use the adjusting slot you must cut and add a 1 inch section of flat stock to the bracket to move it rearward toward the motor because the bracket hits the harmonic balancer . Once welded there should be enough adjustment . Belt size soon.

For the raw water inlet hose you need to remove the clamp , cut the hose at #6 sparkplug , re-route the inlet hose with the flush fitting behind the motor mount cut to correct length and connect to pump.. The outlet hose to the T housing I`m working on. May require a merc hose and joiner fitting

Stay tuned for pics and a final write up

 

[Lou C]

This is replacing the stock Volvo pump that's mounted to the harmonic balancer, correct? Can you replace the Volvo pump with a Sherwood pump as is used on most inboards?

 

[Bt Doctur]

no place to mount one , the last was a Johnson crank mounted and it lasted a year, I service 2 28 Coastals over 26 years old that still have their original pumps
so thats why I went with the merc type .

 

[Bt Doctur]

here`s the mod for the mounting bracket

 

[Bt Doctur]

all figured out except to the raw water to the T housing..Final length of the spacers is 1 3/4 to be machined from round stock. lower adjusting bracket for the PS was lengthened 1-1/6 with plates welded on both sides. Actual length was 1 /1/8 but left is short a bit. Easier to add 2 washers than to cut the welds and shorten it.Short water circ pump bolt removed and a 3 1/2 inch bolt installed. Belt alignment is perfect and a 36.5 inch belt used with good adjustment range
Some preliminary pics

 

[alldodge]

Nice work,
Go figure, I would like to able to use a crank mounted pump but cannot

 

[Bt Doctur]

The raw water side outlet is now complete, using a Dayco hose 1 1/4 x 1 and a 1 inch splice sleeve and you reverse the hose from the T stat to the original crank mounted pump give it a slight twist and connect it with the splice to the Dayco hose end.
will have the pics shortly. The flush hose is moved to the 3rd manifold bolt and installed using a longer bolt and a standoff

 

[Bt Doctur]

Finally Complete, all spacers will be machined from 3/4 round stock , 1 inch hose couplings/joiners/ splice .(3) , 6 hose clamps,
Dayco hose 71596 , original thermostat hose to pump is reversed and given a slight twist to join. From the original raw water inlet hose at the pump cut off the 1 1/4 end so its 3 inches long and save, (pic 1)cut off the 90 deg bend and discard, shorten the raw water inlet hose at #6 spark plug by removing 8 1/4 inches, and use hose splice to join and clamp.Install and clamp Dayco hose , install original thermostat hose reversed and join to Dayco hose with joiner/splice and clamp. Not shown is a ty-wrap holding the Dayco hose in place.,5th pic.
raw water pump pully alum 52822T, steel 73798A1, engine mounted pully 90081T1, pump bracket 89535T

 

[Dave-R]

I like when people can figure out how to solve a problem . Hope this works out. I had a problem with a crank mounted pump that was shaking badly. I took off the pump pulley and rotated it one bolt hole, and that made it happy. Dave-R

 

[alldodge]

Thought about longevity, might want to use a slightly shorter belt on the pump because it appears there is little if any room left to tighten

 

[Bt Doctur]

There is no adjusting for that belt , with the bolts tight there is about a 3/8 ths deflection of the belt center, but those belts are run loose, never tight. The Coastals have about an inch of slack, adjusted that way and have been fine for 28 years .. Where the issue was getting it to clear the 1 bolt head for the timing cover large arrow pushing the pump away from the balancer. Any additional adjusting would need the bottom bolt slot lengthened a bit . Once you install the top bolt , nothing can move inward to loosen the belt