Raw water pump failure and SERVICE BULLETINS (M35B)

[thereefs]

The worst of the worst  happened today.Got back on the boat here in Key West after a 9 month hiatus,cranked up the 35B,started straight away,as usual,but not pumping raw water out of the thru hull,shut it down and pulled the raw water pump and the impellar was trashed,but spinning freely.Yep,broke the camshaft tangs which drive the pump.Anyhow,the local mech.said better off to replace the engine @10k than bother with replacing the camshaft.However after seeing that proposal was not going to fly,he suggested fitting a Jabsco 12V pump(water puppy) as an option.Any thoughts here,actually I think its an upgrade.All you folks with 35b engines make sure you have fitted the camshaft bushing that was not installed on some engines,mine being one.Cheers Dave!

[Ron Hill]

ther : You sure were missing the sleeve/bushing modification (Westerbeke Service Bulletin) that keeps the camshaft attached to the raw water pump shaft.  A costly mistake - that I wrote in our CRITICAL UPGRADES a few years back !

Key West (I've been there for 4 months) is not known as a low cost boat maintenance place.  I know nothing about the Jabsco Water Puppy, but I can't believe that a cam shaft can't be replaced (somewhere else beside Key West) for MUCH less than $10K !! 

Maybe that's why us cold climate sailors pull the impeller when we lay up for the 6 months in the winter.  You need to inspect the impeller anyway after a long lay up or annually, so why not just pull it before - rather than letting it all scrunched up for that time??  We also read the critical upgrades. 

A few thoughts

[thereefs]

Ron,I actually read the upgrade,got the sleave from Universal and never installed it,now Im paying the price!Yes the cost or repair is high,the cam is $1300,the engine has to removed from boat,with about 4-5000 in total labor.The 10k figure was for a new engine,installed.I checked with a Universal dealer ,and found that the Jabsco and the engine driven Sherwood put out about the same gallond per min.,so Ill know in a few days if all is well.In the meantime ,Ill be looking for a mechanic who doesnt charge $120 an hour.If that fails Ill pull it and put it in the back of the truck and take it back to Colorado in the spring and fix it in the garage myself.Cheers Dave

[Ron Hill]

Dave : I'm not too sure if that cam (#200874) is a Westerbeke only or if Kubota may have that part, it might be worth checking.  You might also check the internet to see if that cam shaft is available thru a rebuild facility. It looks to me like the camshaft that works the valves !  The Kubota part may not have the slotted end on the shaft??

I agree with you at the outrageous $$ cost!! It's better to take it home and take it apart yourself.  With the old cam out maybe a good machine shop can duplicate it for (I'll guess) less than $1300 !!  All you need to duplicate is the slotted end!!  It's surely worth a try.

Good luck.  

[thereefs]

Thanks Ron for your concern and advice,you guys are the greatest,now one for Stu,the electrical wizzard,will I need a relay to hook up the Jabsco pump ,or can it be wired directly thru the ign. switch,the pump draws 8 amps?Cheers Dave

[Ron Hill]

Ther : I'll jump in before Stu with a comment.  
Seeing as how it's pumping raw water I'd make sure it's connected to the alternator.  Why? so when the alternator is turning (engine running) the water pumps and when the alternator stops the water stops pumping!!  
My 2 cents, as I've got a turkey on the grill to tend to!!

[Stu Jackson]

Dave, let's see...  Raw water pump goes: thru hull, strainer, raw water pump, HX, exhaust riser nipple, muffler and then out the transom.

You don't want to (over) fill the muffler, so the separate pump should only come on when the engine starts, not before.

That seems to leave out the ignition switch, 'cuz the switch needs to be on for quite some time before the engine kicks over:  glow plugs for anywhere from 12 to 30 seconds.  You don't want to fill up the muffler by essentially "cranking" for that long 'specially if you have to actually try starting the engine more than once.  

Your alternator?  Hmmm, let's see:   There are two possible alternator output wiring shchemes that folks have on their boats.

1)  Alternator wired directly to house bank:  will always be ON because of the connection to the house bank and its negative ground (whether separate or case-grounded through the bracket) - that circuit would always be powered (have power "there") if you connected anything to it (the alternator output)

2)  Through the C post of 1-2-B switch:  same thing when you turn the switch ON.

Conceptually, you want to have that pump run ONLY when the engine is going.

Since heat doesn't build up immediately when the engine starts, a short delay between start and pump run can be accommodated.

One item already exists for this:  the oil pressure sensor.

Consider using that as your "built-in" relay.  Parallel that to your pump circuit.

Only other thing I can think of is a manual switch in the cockpit, or do it down below and just hop down when the engine starts and stops.

Good luck.

[Ron Hill]

Dave : Your oil pressure switch, when it has pressure breaks the circuit to the alarm, but opens the circuit to the electric fuel pump - so I'm not too sure that the oil pressure switch is the answer (8 amps also bothers me in that circuit).

Let me go back to the alternator, as you need 8 amps to run that bugger.  If you could wire in a diode (one way) to the alternator output so that the diode would block the battery current from running that pump (when the alternator is still) and it would only receive current when the alternator is outputting - I believe maybe an answer. 

I'm not an electrical whiz, but possibly a "Zapstop" (it's a one way diode) to that Jabsco would work if it can handle 8 amps.  I'm guessing that 8 amps is at startup and not constant.

Here we are beating our brains out, when Jabsco has probably been asked that same wiring question dozens of times - if that "water puppy" is an electrical answer to the engine driven raw water pump. 
Give them a call tomorrow or Monday at (978)281-0440. 

Anyway it's something to check out.
 

[thereefs]

Thanks for all the knowlege and concern!Got the Jabsco plumbed in,going from the water separator,5/8" to the pump and 1" to the heat exchanger.The hard part was the wiring,impossible to sneak a wire into the Edson pulpit,so used the bilge blower circuit ,unused, and pulled a 16/2 down the portside to power the pump.Used a relay and installed a 15amp.fuse at the panel ,as the pump was kicking the 10amp panel breaker.All is well,runs as before,just dont leave the ignition key "on" for to long.Thanks Ron and Stu,Cheers Dave

[Jim Hardesty]

One of my first projects was to install a combination fuel filter raw water alarm.  The alarm goes off when the fuel filter starts to plug or when the exhaust riser temp starts to rise.  The claim is that the alarm will happen before any engine damage.  Was an easy installation.         
Jim
www.borelmfg.com               800-824-4449

[mainesail]

keep in mind that a RW engine driven pump is a device with flow characteristics that match the engine RPM. Low RPM = lower flow. High RPM = higher flow. An electric pump will pump the same volume at 800 RPM as it does at 2600 RPM. There are plenty of belt drive pumps out there that could be custom mounted/fitted to your engine for far less than 10k..

[thereefs]

Mainesail,quite right,that was considered.This is a temporary fix ,although working well.Im checking out the belt drive one,though as far as I can tell it will have to be a "custom" install,there i,snt much room on the front of the engine to mount a bracket and pump,but Im still researching the options,nothing yet.Cheers,Dave