Westerbeke celenoid keeps failing

[Bonnie Riser]

The celenoid for the fuel primer and the glow plugs on my universal 25 hp engine for the Catalina 28mk11 keeps failing. I've gone through about six of them since I got the boat 1.5 years ago. I use the boat a ton, I've put about 500 engine hours on her and have traveled over 2500 nm. Has anyone had a similar problem or found a solution?

Thanks,

Bonnie Rieser

 

[paulj]

Do you mean preheat solenoid?

Bonnie Rieser

What is the part number of the part you are replacing?

Is the engine you have is a M-25XPB?

paulj

 

[Stu Jackson]

Here are some links for you

Solnoid for glow plugs: http://www.c34.org/projects/projects-glowplugs.html

Fuel Pump: http://c34.org/bbs/index.php/topic,2515.0.html

 

[RichH]

Check the voltage drops (before and after the solenoid)

If there is any resistance in the primary circuit (the circuit from the key-->start button---fuse ---> solenoid--->engine ground strap) the voltage will drop and the amperage will RISE, thus heating up and burning the primary coil of the solenoid. Check the circuit from the control panel .... all the way though to and including the ENGINE GROUND. The corrosion causing the 'high resistance' is usually in the 'connectors' or fuse; sometimes the keyswitch .... but also the 'pushbutton' which may have been arcing and will have a lot of carbon dust inside at the contacts). Usually engine control/starting circuits are assembled from cheap and non-tinned wiring which corrodes quickly in a marine environment.

Get a digital voltmeter and look for a voltage drop in this circuit.

 

[GuyT]

Not right

If the voltage goes down on a solenoid's coil the current goes down.
This effect can be seen by the solenoid "dropping out" because it does not have enough magnetic field strength.
RichH - a solenoid's coil is a wire wrapped around a magnetic structure. The wire resistance is fixed. The field strength is determined by the number of turns and the current(N*I).
If the voltage goes down - the current goes down (ohms law) and so does the field strength. This is why solenoids drop out - they do not have enough field strength to overcome the solenoids spring force.

For a current to go up as the voltage goes down, the load would have to be a constant power or essentially a negative impedance.

A solenoid has an initial voltage/current requirement to engage it(needs high current/field strength) but after the solenoid is engaged, its holding requirements are much lower. I have tested some power relays that need less than half their rated voltage to keep them engaged. There are several circuits that I have used to save power by this phenomenom.

A fix to Bonnies problem may be to get a solenoid that has a higher current rating or one that has better plating on the contacts. Another solution would be to use two solenoids - one for the glo plugs on one circuit and one for the fuel primer on the other circuit. Both would be engaged from the same source(coils in parallel) but the contacts outputs are fed to two different locations.

Simply paralleling two solenoids will not help because although they are the same solenoid, they have slightly different engage times. This difference in engage times(may only be a milli-second) causes one of the relays to take the inrush of current and hence the splash on the contacts. Once they reach steady state current, they will share current but this is usually not the problems with solenoids - they fail (the contacts)because of the arc splash when engaging and dis-engaging. This is where the milli-second of delay will kill!

 

[Bonnie Riser]

Celenoid keeps failing, 1.5 year old boat. Catalina 28mk11

Here is some more information about the celenoid problem, I have gone through 6 of them in 1.5 years. They just keep replacing them under warranty.



Part number

24639 Westerbeke part number for celnoid for glow plug. Westerbeke has not come up with a reason for the repeated failures. I do not know who westerbeke buys the celenoids from. It says they are assembled in Canada.

My engine is a Universal 25XPB.

Bonnie Rieser
Catalina 28 MK11
Hull 832

http://catalina28.blogspot.com/

 

[Bonnie Riser]

solenoid failing over and over

Hi All,

Stu - Are you suggestions using two solenoids? Replacing the one I have with he Napa fuel pump and using a separate one for the glow plugs? What would I use for the glow plugs? Would they both use the existing wiring?

My engine starts by holding the key over. I usually hear a tick, tick,tick of the fuel primer. The same solenoid also warms the glow plugs. I think 3 amps go to one and 7 to the other...

Stu, are you and Guy agreeing with each other?

Guy -- I will be hiring somone to fix it so if I can just tell them what to do or look at... Do you know of solenoids that have higher current ratings or better plating?

Thank you all for your help.

Rich -- I will have a friend read your input and lok for corrosion.

Bonnie

 

[GuyT]

For that amount of current,

You should be able to use a standard automotive relay like a Tyco VF4 series. Tyco VF4A-45F11 is a good part.
It has a 40 amp rating for the Normally open contacts.
Here is a link to purchase the part from Mouser Electronics.
Also on the link will be a Song-Chuan 896H-1CH-D1-12VDC
part. It is also a good fit.

These parts may not be direct replacements for your solenoid but if you know how to hook them up, they will definately work - as long as you are correct with the total current not exceeding 10 amps as you posted.

Good luck.

 

[Stu Jackson]

Along thread with some implications for you

and others with "improved" Universal engine wiring.

Bonnie, the thread is very long, but you may enjoy reading all of it. My conclusion was that the improved wiring arrangement is not necssarily an improvement. I do NOT know what you have on your boat, but it seems similar.

The Napa fuel pump is just a pump, and on our boat it has no solenoid, just the key switch turns it on, as well as energizing the cockpit panel switches for the glow plugs and start buttons.

The glow plug solenoid has become, I understand, a standard on the later engines. It was not made with the M25 engines, and I do not know if they came with the M25XPBs. I'm pretty sure they now come with the newwer M35s.

Only you know what you have on your boat, I was just pointing to two resources for you to consider which may be applicable to your situation.

 

[Bonnie Riser]

Celenoid keeps failing, 1.5 year old boat. Catalina 28mk11

Hi All,

I talked with the warranty dealer about some of these ideas and he feels the first thing to try is to get the solenoid off the motor. He feels it is the shaking of the motor that is breaking them. So he is trying/working on getting approval from Westerbeke to remote mount the solenoid on some nearby bulkhead and extend the wiring. The warranty covers replacing the solenoids, but perhaps not doing other work to make them stop breaking...

Thank you all for the input. It gives me a lot to work with.

Bonnie