Question about emptying carb during periods of non use

swc65 said:

I think we are getting somewhere! See my posted pics of solenoid and wiring diagram from the manual. Looks like they match to me.

So based on this confirmed information, is my diagram correct? I it seems matches what Sierra sent me. I like the Makomark is thinking but again, I want to do what is right and safe.

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swc65 said:

Thanks Mark but I'm confused. If you blow up the pic there is an R on the terminal. Do I still need the momentary switch? I must me missing something. It looks just like the manual. I do like the idea of having a momentary to give the carb a shot fuel so not a deal breaker, I'll just have to swap out an existing rocker which I have my radio wired to or drill a hole in the helm which I'd prefer to avoid.

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makomark said:

What you see on the starter's solenoid end cap is the "R" designator - there is no threaded terminal, so there's no finger to pass any current when the solenoid is engaged.
Mark is correct!
The "R" is cast into the plastic but they omitted the R terminal stud and contactor.

When/if the R terminal is used, it's small internal contact provides momentary power just as the lower 6:00 O'clock position armature power supply stud does.
When the solenoid disengages and releases power to the armature, the R circuit would also disengage.

You can add the momentary switch, if you want to, with a minor modification to the diagram.FWIW, it does NOT have to be on the dash....you can put it anywhere it is convenient as long as its a modestly well protected area. Just remove the wire between the starter solenoid's S terminal and the oil pressure switch. Wire the switch between a protected +12VDC source and the feed to the pump (from the "P" terminal of the oil pressure switch)....no real benefit to having the pump engage with the starter if you have the momentary switch.

Agreed.
With a momentary switch (helm or elsewhere), you do not need to crank the engine over in order to achieve fuel pump operation and carburetor priming.

Believe it or not, by using that system, you will extend the life of your starter motor and cranking battery.

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RicardoMarine said:

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With the above connection (short yellow/red stripe wire going from the "Common" cable connection to the S terminal), the moment that you turn your MBSS on, the yellow/red stripe wire will trigger the starter motor solenoid.
This is a NO NO!
I don't have a MBSS (batter disconnect?)
If your system uses a "slave solenoid", the slave will trigger the starter motor's solenoid for you.
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I do have a slave solenoid. The Yellow /Red Stripe wire from the the ignition at the helm is terminated at the slave solenoid. The red wire in the above pic is connected to slave solenoid. I don't understand what function the short yellow/red stripe wire is performing. See pic from manual. Current wiring matches manual.

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swc65 said:

RicardoMarine said:

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With the above connection (short yellow/red stripe wire going from the "Common" cable connection to the S terminal), the moment that you turn your MBSS on, the yellow/red stripe wire will trigger the starter motor solenoid.
This is a NO NO!
I don't have a MBSS (batter disconnect?)

All due respect..... why would you not have an MBSS, or at least a BS?
The MBSS (main battery selector switch) allows you to:
.... shut down all 12 vdc when you leave the boat unattended.
.... select between battery banks.... I.E., between your dedicated starting battery or your HLBB (house load battery bank).

With no MBSS and only one battery, you have no reserve.
If by chance you were to deplete the one battery (due to radio, FF, DS, or other 12 vdc extended usage), how do you plan to start your engine?

Most of us will have a dedicated cranking battery on MBSS terminal #1, and a dedicated bank of Deep Cycle batteries on MBSS terminal #2.
Start engine on #1, warm engine as the #1 charges, then switch to #2 and go have fun.

If your system uses a "slave solenoid", the slave will trigger the starter motor's solenoid for you.
[/QUOTE

I do have a slave solenoid. The Yellow /Red Stripe wire from the the ignition at the helm is terminated at the slave solenoid. The red wire in the above pic is connected to slave solenoid. I don't understand what function the short yellow/red stripe wire is performing. See pic from manual. Current wiring matches manual.

View attachment 23253


OK.... if your system is wired as per the schematic, your "common" cable (the cable coming from the "Common" post of your MBSS) makes it's connection to the slave solenoid.
That is why you have the short yellow/red stripe wire running from the upper lug to the S terminal on the starter motor.

In other words, YOUR slave solenoid is NOT first powering the S terminal (at the starter motor's solenoid), it is actually powering the main lug at the starter motor's solenoid.
As this lug receives power, it simultaneously powers the starter motor solenoid's S terminal.

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makomark said:

No R terminal on that solenoid.....so you have to use the SPDT pressure switch.

Based on the part numbers provided, your diagram looks fine.

I'd suggest adding the wires' color codes and adding it to your maintenance log....and getting a spare switch to have on hand....they always fail on Sat afternoon when the weather forecast calls for a beautiful boating Sunday....

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swc65 said:

I have having difficulty identifying the correct switch to use. Can you recommend one?
What switch are you referring to?

I have scoured the internet looking specifically for a Marine grade SPDT.
SPDT typically means single pole/double throw, as in a toggle or a rocker switch.
Is that what you're after?

Low Oil Pressure Saftey switch. All I find are three prongs and not two.
Here is a Holley 12-810 Holley 3 pole Pressure Switch, of which is most likely a Hobbs.
This will offer both N/C and N/O contacts, with one terminal being "common" .

Here is another version using only two poles. This will be N/O.


Both use the 1/8 NPT thread.


Can an automotive switch be used? I have read multiple posts about switches being either 1/8" or 1/4". Mine seems to be neither based on pics below.
You most likely need 1/8" TPT (tapered pipe threads).



When I find the SPDT low pressure switch, It will be installed in the same TEE with the Oil Pressure Sender.
Again, SPDT typically refers to single pole/double throw, as in toggle or rocker switch.

I removed the existing Oil Pressure Light Switch as identified on this site's Engine Diagram trying to confirm for connection size. The part is obsolete and I cant find the thread pitch and diameter. I took it to an auto parts store to size the thread and the closest I could come is M10 1.0 Even then the switch only threaded in 1 1/2 turns. I took pics but having difficulty getting new pics uploaded on this site.

This seems very strange to me. Am I missing something? I can't imagine the sensor was metric as OEM.
Correct... for an American engine it will be 1/8" TPT.

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swc65 said:

Excellent. I just thought the diameter was way to big on the current idiot light. It measures about 3/8 with Tape measure.
The threads on the idiot light switch?
Yes, they will be 1/8" TPT, which will measure approx 3/8" at the OD.


Hope the installation TEE will seal with 1/8”. the taper at base of switch will need to be large enough to seal. Guess I’ll know when I crank it over... I may take the tee out and go to marine shop to actually test fit.

1/8" TPT is 1/8" TPT all day long and where ever it's used.
The male threads are tapered.
The female threads are also tapered.
The interference between the two is what creates the seal.

Do not use Teflon tape for this application ......... instead, use a thread sealant.

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swc65 said:

Thank you. Good to know on the StaBil. I used to use it all the time but when I switch to Ethanol free, I didn’t think I needed it any longer. My mistake.
If you are using Non E-10 gasoline, you should be OK during each winter lay up.
Fuel problems are more likely to occur when boats sits through a warm summer or two.

Not sure I’m up to I stalling the check valve. Look pretty easy but I’d hate to screw it up and have to buy a new carb. I’m “hoping” that with a correctly sized fuel pump that delivers appropriate pressure l, and when I complete a full ReNew kit and when I confirm they my total timing is good, I will.
I have back fires to deal with.

Are you using a Marine ignition system, or Automotive with a vacuum advance unit?

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RicardoMarine said:

Are you using a Marine ignition system, or Automotive with a vacuum advance unit?

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RicardoMarine said:

ll due respect..... why would you not have an MBSS, or at least a BS?
I did not know I needed one. This is my first boat, I always keep it on trickle charge when not using and am religious about monitoring my voltage gauge. After reading your post, I realize that I need one but it further down on my list at the moment. I'm focus on getting the fuel system to compliance and the chronic "rich burn" issue solved. I'll have some follow up questions on your earlier posts. Sorry for so many but I am realizing the at I don't know what I don't know...

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swc65 said:

RicardoMarine said:

all due respect..... why would you not have an MBSS, or at least a BS?

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I did not know I needed one.
You do not necessarily need one, but without, you have no means of isolating your battery when you leave the boat unattended.

If you install an MBSS, you can have two battery banks...... one for engine cranking, and one for your House Loads.
The #1 bank will be held in "reserve".

This is my first boat, I always keep it on trickle charge when not using and am religious about monitoring my voltage gauge. After reading your post, I realize that I need one but it further down on my list at the moment.
FYI... trickle chargers should be thought of as Battery Killers.
You want a "smart charger" with a float or a maintenance feature.


I'm focus on getting the fuel system to compliance and the chronic "rich burn" issue solved. I'll have some follow up questions on your earlier posts. Sorry for so many but I am realizing the at I don't know what I don't know...
There are NO stupid or dumb questions.
We are here to offer our help to those who ask for it.

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RicardoMarine said:

You do not necessarily need one, but without, you have no means of isolating your battery when you leave the boat unattended.

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​RicardoMarine said:

FYI... trickle chargers should be thought of as Battery Killers.
You want a "smart charger" with a float or a maintenance feature.

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daves69 said:

Late to your party but getting back to your original post, if you are blowing out power valves there may be other issues. Holley has a backfire blow back check retrofit for older carbs without.
https://www.holley.com/products/fuel_systems/carburetor_components/power_valves/parts/125-500

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daves69 said:

FWIW, I use Stabil in ALL the gas that goes into my boat tank. It has had only 10% ethanol gas with Stabil since '08 when purchased new. It has never seen salt water here west of the windy. I double the Stabil dose for winter layup with a full tank. I'm thinking my layup season is longer than yours. I haven't taken my boat out of the winter wrap as yet for this year. Our Governor has us set up for another 30 days in the hold right now. Anyway, I have never drained the Holley 2300 out at season end. In 2016 (8 years of never draining) I pulled the carb off to clean out all the muck and scale I was sure it had collected.
I was astonished by what I didn't find....................
View attachment 23270View attachment 23271

I saw nothing of what I was expecting. Re-assembled it, re-installed it, and called it a day.

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RicardoMarine said:

What is best way to check the TA at 3200 RPM?
You can use one of two methods:
.... a digitally advancing timing light as you increase RPM.
.... a degree marked off harmonic balancer and a standard strobe style timing light as you increase RPM.

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swc65 said:

Rick said:

What is best way to check the TA at 3200 RPM?
You can use one of two methods:
.... a digitally advancing timing light as you increase RPM.

.... a degree marked off harmonic balancer and a standard strobe style timing light as you increase RPM.

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Want to be sure I understand this correctly. I only own a basic timing light for base timing.
You can use the standard strobe style timing light for setting BASE, looking at the progressive and for looking at the TA.
In fact, I prefer this style because it allows us to see Real Degrees in Real Time.

With the second method, am I understanding correctly that the harmonic balancer would be marked off with Total Advance degrees.
The balancer would be marked off in degrees, which will represent any ignition timing advance (per RPM).
This will include the the range where total advance will occur.

Your engine is a standard LH rotation ( CCW when viewed from the flywheel end ).
As you look at the front of the engine, the harmonic balancer will turn CW.
You will see the TDC markings, both on the harmonic balancer and on the timing tab.
Any degree of advance will be to the right of the TDC mark.
In other words, if you install a timing decal (aka timing tape), the ZERO will align with the TDC mark, with the additional degrees to the right..... or CW from the TDC mark.

With the engine running, the strobe light will illuminate the markings before the #1 piston reaches Top Dead Center.
After you set BASE advance, you will increase RPM as you continue to strobe the marks.
You will see the system advance.
As you reach the "Full In" RPM (should be around 3.2K rpm), the system will stop advancing.
That will be your TA (total advance).


The index on my engine only goes to ~12 degrees if I recall correctly?
Yes.... that is why you need to add marks or apply the timing degree decal.
NOTE: the diameter of the balancer will determine which decal you purchase.


SO, I can not check TA with my standard strobe and my current harmonic balancer, correct?
Your strobe light is OK, it's the markings that will need to be extended up to approx 35 degrees.





Or is there a method of marking more degrees on my harmonic balancer?

Yes, either by:

a...... transferring degrees onto it
b...... applying a degree decal
c...... purchasing an indexed balancer


...... When put the light on it late last week, it went past the scale at 2000 RPM. I backed off of it because I was confused.
Yes, if marked to 12 degrees only, as you increase RPM the ignition will advance past 12 degrees, and off your scale.
You simply did not have enough degrees on the balancer to see where the advance was at that RPM.



By the way..... if you apply the timing decal, be sure to solvent clean the OD of the balancer before applying it.

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makomark said:

What you see on the starter's solenoid end cap is the "R" designator - there is no threaded terminal, so there's no finger to pass any current when the solenoid is engaged.

Click to expand...

makomark said:

You can add the momentary switch, if you want to, with a minor modification to the diagram.FWIW, it does NOT have to be on the dash....you can put it anywhere it is convenient as long as its a modestly well protected area. Just remove the wire between the starter solenoid's S terminal and the oil pressure switch. Wire the switch between a protected +12VDC source and the feed to the pump (from the "P" terminal of the oil pressure switch)....no real benefit to having the pump engage with the starter if you have the momentary switch.

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swc65 said:

OK, So I've think I now have a plan please let me know your thoughts.

Found momentary rocker that would fit in my helm line up. I modified my diagram. I plan to terminate the momentary rocker on the "P" Terminal on the N/O LOP switch along with a wire from the "P" terminal to the Fuel pump. Any think wring with this? Or any improvements?

The "I" terminal at the key switch already powers the instruments and the ignition coil.
The circuit run from the key switch to the engine is rather long.
When we place an additional load on this circuit, we create additional resistance.
This is exactly why I suggest using a relay that would be triggered by the N/O low oil pressure switch and by the momentary helm switch (in lieu of a "start by-pass" circuit).
The load to trigger a relay is very small.
The relay's power would come from a much closer source.

Your call on that!

I will plan to run the pump after the water separator. Its not shown here. Also plan to install an in-line pressure gauge to determine if I need a regulator.
You should not need a fuel pressure regulator.
The electric fuel pump is designed to produce a pressure range (4 to 7 psi) that is suitable for your carburetor's needle/seat.
If you do check the fuel pressure, remove the gauge afterwards.


Any coaching on wiring and terminating in marine applications.
I have been researching Crimp & Heat Shrink connectors vs Self Solder connectors. I don't have experience with either. I have learned that I need to use marine wiring.

The alleged "self sealing" wire fittings pose an issue.
Unless you have experience and the proper crimp tool, often the pre-applied shrink tube becomes damaged during the crimp.
You will not see the damage at this point.
Once heat is applied, the shrink tube often splits at the point of crimp tool contact. So now you end up with a fitting and a breached seal! Not good!

You will do much better if you use bare fittings (no plastic insulator) with standard self sealing shrink tube that was first slipped onto the wire.
Make your crimp.... slide the shrink tube over the freshly crimped fitting.......... apply heat......... done.

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makomark said:

I think your diagram is fine.....
Yes, it will work.
However, it would not be my choice due to the reason that I have explained.

a decent crimping tool is a must and there's nothing wrong with the heatshrink terminals.....they've been around for decades...
Mark, yes, they have been around for decades. We simply agree to disagree as to their safe use.

I've seen my share of the "heat shrink" wire terminal failing at the point of the crimp.
That material is too soft and fragile to be crimped over, even with the correct crimp tool.
I will not use them when it's just as easy to use bare fittings, and then slide the self sealing shrink tube over them.
IMO, you'll end up with a much better wire fitting.



like with any crimper, you need to pay attention to what's happening. The best crimpers are used in the aviation industry, require calibration (checking), and will cost you well over a grand brand new....most people don't find them cost effective...
Yes... and having been in this business, the high quality crimp tools are the only ones that have owned and used.
They will also last for years and years.


By the way and for what it's worth...... you will not see the pre-applied/self sealing shrink tube style wire terminal being use in an Aviation application.

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RicardoMarine said:

The "I" terminal at the key switch already powers the instruments and the ignition coil.
The circuit run from the key switch to the engine is rather long.
When we place an additional load on this circuit, we create additional resistance.
This is exactly why I suggest using a relay that would be triggered by the N/O low oil pressure switch and by the momentary helm switch (in lieu of a "start by-pass" circuit).
The load to trigger a relay is very small.
The relay's power would come from a much closer source.

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