Update on AQ255 raw water pump see Aug 13

Update; replaced impeller and

Update; replaced impeller and O-ring and pumped fine from bucket in bilge with engine running. Problem was mostly the Globe dry-run impeller (used only 2 short seasons). Think I'll switch from Sherwood pulley driven pump to Johnson crank driven pump. So would like info on how to do and what model pump. Looks like I did damage the AQ280 exhaust bellows flapper when I ran engine briefly w/o water thru manifold/risers last week; metal flapper support came out with exhaust upon startup this am.
Looks to me like I can change exhaust bellows w/o pulling upper gear hosuing if I tilt I/O way up. True??

"Bruce, you have more than lik

"Bruce, you have more than likely damaged the exhaust couplers as well. I'd replace these as well as the bellows.
As mentioned, you are better off retro-fitting a 290 flapper onto the 280 drive exhaust outlet, than to have this restrictive flapper in the bellows for a V-8 engine... This is just my opinion!

Fit the new bellows onto the Y pipe exhaust outlet first, and install the Volvo Penta OEM clamp.
Place the weep hole FWD and DOWN.
Now make and tie yourself a wire harness affair onto and near the AFT end of the bellows to assist in pulling it onto the Intermediate housing.
No need to remove the transmission unless you want to more easily check/replace the water neck fitting and gasket (of which I would highly recommend doing)!

The Johnson crankshaft pump would be a real plus for this engine.
You will need to make sure that you have room for the crankshaft pump. They sit forward of the harmonic balancer approximately 4- 1/4" plus you'll need a small amount of space to R&R the impeller.
The F5B-9 is a good choice for this engine. Impeller is a very common #1027.

Here's the good part:
You can eliminate the original OEM bracket, pump, belt, pulley, etc..... and can now expose the engine timing marks for easier timing!
This also makes impeller change and winter removal easy, and so on.
This is a very good improvement over the system that you currently have.


The factory crank pulley will have two raised areas on the front within the recess of the pulley........ we'll call these "Alignment Dowels".
These dowels align the Johnson pump base.
They are not symmetrical.
The pump must be indexed to these dowels.
The three bolts will be replaced with socket head bolts.

The hose after the pump to the thermostat housing, can be an automotive radiator hose w/ the pre-formed bends if need be.
If you can talk your way into the radiator hose section at a parts store, you will no doubt find a hose of the correct shape and size to work..... it need not be wire re-enforced on this side of the system (pressure only here).

Barr makes and sells a retro fit alternator bracket that uses the two # 1 cylinder exhaust manifold bolts..... it works great when doing this conversion.
p/n CHV 27-0083
http://www.marineparts.com/mpf/mpf273.aspx


I've done this more than once..... trust me, it works!"

"Hi Rick, Thanks once again fo

"Hi Rick, Thanks once again for the meaty reply. I presume by "exhaust couplers" you mean the 4" to 3" rubber tubes from risers to ends of Y-pipe (These tubes necessitated by switch from old one piece manifold to riser/manifold combo. I also had to add a 3" SS elbow on downstrem side of tube and above Y-pipe.) I have them and definitely will replace. Thanks for tips on exh. bellows install. I'll think more about the 290 flapper, but I'm pretty sure the bellows I'm pulling is the factory original on this 1978 boat! I assume you're bothered by back pressure from flapper in bellows, but at my age and the boat's age, I go pretty easy on the throttle so a little power loss isn't a big deal! I ordered a new water neck along with the new bellows. Looks to me like that should also come out with the trans in place, (probably need to detach aft end of drive bellows tho) unless the 2 socket head bolts are badly seized. (I've been squirting Blaster on for a week.)
I really appreciate the water pump conversion info. My pulley driven Sherwood is pretty worn and corroded. I'll probably do that before winter layup.
One other question; I did the base timing today, but will hold off on TAT until I put boat in lake in a couple weeks. I converted the ignition over to Delco HEI. They say to connect wires to "time" for (base) timing, then switch back to "run" mode for normal operation. Do I put it in this "time" mode for 3000 rpm total advance timing?"

"Bruce, you're very welcom

"Bruce, you're very welcome.

Yes, the rubber coupling components that connect the risers to the Y pipe. Check the insides of these.

As mentioned to you on the phone, the water neck can be replaced while the transmission is in place..... it is more difficult, and if you have any corrosion issues with either of the two screws, it becomes even more difficult.
If you even ever-so-slightly suspect that these screws are not cooperating, I'd caution you!
I almost always apply some heat to the suspension fork (at this area) to help with any corrosion issues.

I don't use the Delco ignition, I prefer the YLM 624 AV for this engine...... but any "Base" mode is used for setting BASE only!
When checking TA, you do not use BASE mode....... just keep it in the normal operation mode for this. (unless the ignition uses a computer, knock sensor or ???, the engine <u>need not be under load</u> to set TAT)

Once you get that AQ 200/AQ 255 pump bracket out of your way, and the crankshaft pump installed, checking/setting TA becomes very easy to do.

."