Is the Boost Solenoid Necessary?

> Well if any one knows where I can find a replacement, please let me know. I've checked the forums and Applied's web site, but only see starter
> ones listed. I have no problem replacing it; right now it still is operable (and yes I have used it once or twice in the past).
>
> Thanks everyone for the help.
>
> Brian

Here is the correct solenoid:
https://www.amazon.com/dp/B0064MX7US/?coliid=I2J30CLAFH1UVR&colid=229ZBOWGLP3SW&psc=0&ref_=lv_ov_lig_dp_it
--
JD Lisenby- USAF Ret
1978 Royale-455
MacDash, Manny Tranny, FI-tech, 3.70 etc etc

Navarre, FL
 
Ken,

I like the three switches because they follow the KISS principle and they have worked well since they were installed in 2008. In fact I just bought
three more to install in the Kingsley.

I agree if a battery catches on fire access would probably be compromised. However, if the fire is already big enough prohibit access to those
switches would shutting off the batteries make any difference?

I would open the hood and extinguish the fire with AFFF and then turn off the switch.

--
Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
 
interesting thread.. makes me think a key fob remote to control the switches with would be very useful too. not sure if there is anything made just
for that but some aftermarket alarm systems have extra outputs for various purposes and could also do this.
 
The Boost relay / solenoid is NOT your problem. Under normal operation the boost relay is not activated the contacts are not used. Under normal
operation the relay is used as a simple terminal block for two connections. #1 is the engine side battery cables. #2 is the house side battery
cables.

When the solenoid is activated it hooks the batteries together. When not activated the relay is simply two terminals. Since it is not used
(activated) in normal starting it is not causing your hard cranking problem. I suggest that you look at battery cables and connections between the
starter and the battery. This includes the battery cable connection on the boost solenoid. Remove every one of them and clean thoroughly until
shiny. Reassemble them with anti-oxidation grease and see what you now have. Do not forget the ground cable which also must be shiny and attached to
the engine block.

If you want to diagnose it farther with a meter, put your meter across the battery (not the battery cables) and crank the engine. read the voltage. It
should be somewhere around 10 volts. Now move the meter to the big cable on the starter and engine ground. Crank the engine and read the voltage
again. The difference between the two readings is what you are loosing in the cabling / connections between the starter and battery. It should only
be a few 1/10ths of a volt. If it is higher than this you need to find the loss.

The next question is, is the loss on the hot (+12) side or ground side. Leave the positive cable attached to the big starter cable and move the
negative cable to the POSITIVE battery terminal. Crank the engine and read the meter. This is the voltage loss in the positive side wiring/
connections. Move the meter to the engine block and negative battery terminal. Crank and read. This is the negative side loss. Now go fix / clean
which ever side had the most cranking voltage loss.

If all of the above readings were good then now is the time to pull the starter.

In every case where I have worked on a hot start cranking problem, the issue turned out to be advanced ignition timing or battery cabling and
connection issues.

Starters do fail but many times the problem is not really the starter.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
As to hot starts, if your tests, suggested by Ken Burton, show a drop between the starter & the battery, I suggest using Gene Fisher's idea of running
a new cable directly from the battery to the starter. Remove the starter end of the cable that runs from the boost switch tie point to the starter,
and connect it to the battery. I use a dual terminal battery to make this easier.

Worked for me, John
--
John Shutzbaugh, Vacaville, CA, ncserv;
77 Eleganza, bought it new, can't blame PO, and
78 Buskirk stretch, "What were we thinking?"
 
The boost solenoid is out of circuit path during normal cranking. It simply provides a binding post for the 2 engine battery cables to join and
continue. You cleaned "most" of your connections. Did you clean them witth something like Caig D5? You did not clean all of them and resistance in
series is additve. You need to also load test your engine battery. I believe you have multiple problems contributing. Is your hot starting a no
starter engagement or slow labored cranking. You don't actually clarrify. My 455 cranks faster than any GM car I have ever owned under all conditions
and with a old starter.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
It would be much more work to circumvent the boost solenoid than to bolt in a fresh one because it serves as a junction
block for all those cables. Any short there has fire potential.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
I have one of those battery kill switches in place, so the main "hot" line goes to that, then there is a line from the switch to the boost solenoid.

So, one thing I did notice when I got home this week, and started looking at the wires, was that the line to the starter goes directly to the boost
solenoid. So I have removed it from the solenoid, and moved it directly to the side of the "kill switch" where the hot wire comes from (i.e. both the
battery hot line and starter line are now directly touching. Unfortunately, my chassis battery is on the driver side, and there are a spare set of
house batteries on the passenger side. I would have to get a new line directly from the starter to the battery, or switch the batteries around.
Either may be the next solution.
--
Brian K
1977 Eleganza II, TZE167V100261
Bellevue, WA
Rebuilt 455, New brake system, a lot of Original Equipment ready to fall apart (discovering more as I go along....)
 
> The boost solenoid is out of circuit path during normal cranking. It simply provides a binding post for the 2 engine battery cables to join and
> continue. You cleaned "most" of your connections. Did you clean them witth something like Caig D5? You did not clean all of them and resistance
> in series is additve. You need to also load test your engine battery. I believe you have multiple problems contributing. Is your hot starting a no
> starter engagement or slow labored cranking. You don't actually clarrify. My 455 cranks faster than any GM car I have ever owned under all
> conditions and with a old starter.

John, I went through this in detail in my earlier post (see the first post here for a link), so I didn't want to repeat all of that again (ad nauseam
and bore people who had already read it). In short, the problem I was having was at took a long trip from Seattle to Los Angeles. When I drove a
long stretch 2 to 4 hours, and stopped at either a rest stop, gas, or Walmart, when I got back, I got nothing when I turned the ignition key. I had
over 12.5 in battery power, but nothing. I managed to get it started twice (once with a jump, the second time by me taking off the cables from the
chassis battery). When I reached a destination, and plugged in or hooked up my battery tender, it would start without a problem (hot or cold).

When I was in LA, I went to Pep Boys and bought some battery cleaner and some protectant. I cleaned all of the upper connections (in the front
compartments.
--
Brian K
1977 Eleganza II, TZE167V100261
Bellevue, WA
Rebuilt 455, New brake system, a lot of Original Equipment ready to fall apart (discovering more as I go along....)
 
> John, I went through this in detail in my earlier post (see the first post here for a link), so I didn't want to repeat all of that again (ad
> nauseam and bore people who had already read it). In short, the problem I was having was at took a long trip from Seattle to Los Angeles. When I
> drove a long stretch 2 to 4 hours, and stopped at either a rest stop, gas, or Walmart, when I got back, I got nothing when I turned the ignition key
> (no cranking, no clicking, no sound). I had over 12.5 in battery power, but nothing. Everything else worked. I managed to get it started twice
> (once with a jump, the second time by me taking off the cables from the chassis battery). When I reached a destination, and plugged in or hooked up
> my battery tender, it would start without a problem (hot or cold).
>
> When I was in LA, I went to Pep Boys and bought some battery cleaner and some protectant. I cleaned all of the upper connections (in the front
> compartments). I did load test the battery. I charged it to full, and then cranked it with a meter. It held at about 12.7 after cranking, and
> didn't drop below 10 that I could tell when I cranked.

Brian,

I have a similar symptom to what you are experiencing. Every since I purchased the coach 11 years ago, it sometimes will not do anything when I try to
start after we having been driving for a while. I monitored the voltage while trying to start and found that there was not a voltage drop which told
me that starting level current was not getting to the starter. As a diagnostic aid, I ran a wire from the solenoid up to the battery area. The next
time I had the problem, I went out an touched the wire to the battery and the engine started which told me that the starter and solenoid was OK and
that there was another problem somewhere between the ignition switch and the solenoid. Because Margie was getting tired of going out and touching the
wire to the battery (especially in the rain), I put in a relay and ran wires into the cockpit connected to a momentary switch so that when I energized
the relay, the engine starts. Margie appreciated the effort. Obviously, I should fix the problem. In fairness, I did replace the NSS to no avail. I
now believe the ignition switch to be the culprit. But, hey the work around has worked for 11 years so why hurry.

On our way home from a 2500 mile trip to Wash DC with a couple of grandkids, I experienced the same no-start issue. I hit the momentary switch and
still nothing. Monitoring the voltage showed that the voltage dropped to 10 volts while trying to start - hmmm, this is different. So now, I suspect
the starter or solenoid. I slip under and tap on the solenoid and starter with a hammer while Margie successfully starts the engine. Next stop is for
gas, no start so Margie pushes me out of the station with our little Honda HRV towed. I try the hammer - no joy! I'm thinking this is heat related so
I asked the grandkids if their water bottle squirted water. They were quick to demonstrate. After drying myself off, I crawled under and squirted the
solenoid and starter and it started up and off we went. After overnight, it would start normally so I got gas early in the morning on the remaining
trip home.

Back home, I now have a new starter and solenoid and will be inspecting the old for evidence of a problem. I suspect the starter because there was
such a voltage drop. I will check the starter brushes - maybe they are toast.

I plan on changing the ignition switch soon, hopefully, before another 11 years pass.

--
Randy & Margie
'77 Eleganza II '403'
Battlefield, MO
 
> > The boost solenoid is out of circuit path during normal cranking. It simply provides a binding post for the 2 engine battery cables to join
> > and continue. You cleaned "most" of your connections. Did you clean them with something like Caig D5? You did not clean all of them and
> > resistance in series is additive. You need to also load test your engine battery. I believe you have multiple problems contributing. Is your hot
> > starting a no starter engagement or slow labored cranking. You don't actually clarify. My 455 cranks faster than any GM car I have ever owned
> > under all conditions and with a old starter.
>
>
> John, I went through this in detail in my earlier post (see the first post here for a link), so I didn't want to repeat all of that again (ad
> nauseam and bore people who had already read it). In short, the problem I was having was at took a long trip from Seattle to Los Angeles. When I
> drove a long stretch 2 to 4 hours, and stopped at either a rest stop, gas, or Walmart, when I got back, I got nothing when I turned the ignition key
> (no cranking, no clicking, no sound). I had over 12.5 in battery power, but nothing. Everything else worked. I managed to get it started twice
> (once with a jump, the second time by me taking off the cables from the chassis battery). When I reached a destination, and plugged in or hooked up
> my battery tender, it would start without a problem (hot or cold).
>
> When I was in LA, I went to Pep Boys and bought some battery cleaner and some protectant. I cleaned all of the upper connections (in the front
> compartments). I did load test the battery. I charged it to full, and then cranked it with a meter. It held at about 12.7 after cranking, and
> didn't drop below 10 that I could tell when I cranked.

OK my previous posting was a result of my misunderstanding of your problem.

Now Simply put, when it fails the solenoid fails to operate. There is no noise, no clicking, no nothing.

So now we need to determine if this failure to operate is an electrical or mechanical problem. My approach to this would be to get about 6 or 8 feet
of 14 gauge or larger wire and connect one end to the small terminal on the starter solenoid. That terminal should already have a 12 gauge purple
wire on it. I would run that new wire up to the area near the isolator and boost relay BUT DO NOT CONNECT IT to anything. Insulate the open end of
the wire with anything like tape or a wire nut to keep it from accidentally shorting to something.

Now the next time it fails do one of two things.

1. Attach a voltmeter plus side to the wire you ran and the negative side to the aluminum plate that the boost relay and isolator are mounted on.
Try to start it and read the voltage. If you have 12 volts when attempting to crank, then you have a starter bendix mechanical, or solenoid
mechanical, or solenoid electrical problem.

If there is no voltage then you have an electrical problem which is usually Neutral Safety Switch or ignition switch. This could be either electrical
problem or mechanical adjustment of either one. You will have to get in there with a meter or a test light to figure which one is the problem.

2. The second way to test this is to take the open end of the new wire that you just ran and connect (touch) it to +12 volts. +12 volts is available
several places right around the boost solenoid including the big nut terminal that is labeled vehicle positive. Connecting it will supply +12 to the
solenoid and the vehicle should immediately crank no matter where the ignition key is positioned. That will get you going again and you can shoot the
problem later if desired. If it cranks it also tells you, like item one above, that you have an electrical problem in the NSS or Ignition switch
area.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Randy and Ken, thank you very much for the input. All of this is very helpful, especially to a semi amateur mechanic like me.
--
Brian K
1977 Eleganza II, TZE167V100261
Bellevue, WA
Rebuilt 455, New brake system, a lot of Original Equipment ready to fall apart (discovering more as I go along....)
 
For me, the combiner is a locking boost switch. When the generator is
running, the combiner is combined and the engine is running off the
converter. if the converter can't make the combiner connect, then it won't
power the engine, either.

I have never really needed my boost switch, though I do keep it maintained.
I'm using a 200-amp continuous-duty contactor that I bought from a
combiner manufacturer who had changed their design and surplussed off the
contactors. It's about twice the size of a typical solenoid switch and it
gives a satisfying click when engaged.

But I have have dealt with an alternator failure by removing the wire,
starting the generator, and running off the converter. Worked fine, though
I might not want to do it at night--the headlights, along with everything
else, might exceed the 40-amp capacity of the converter.

Rick "who had a problem once when a Toyota alternator couldn't keep up with
four sets of driving lights for a car set up for night rallies" Denney

On Fri, Jul 13, 2018 at 6:06 PM, Ken Henderson
wrote:

> ...
> How do you folks with momentary action boost switches handle the situation
> when you need to use the Onan to power the engine? I'd sure hate to be
> without my locking boost switch. In fact, if I had one of the momentary
> ones, I'd try removing the spring to see if I could make it lock.
>
>
>

--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com