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Add starting relay

Oct 29, 2005
2,094
Hunter Marine 326 303 Singapore
I would like to fit an additional starting relay as I'm tired of the "hit or miss" starting issue with my Yanmar 2GM20F. Could anyone share their setup wiring diagram with me? Much appreciated. :)
 

Tom J

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Sep 30, 2008
1,660
Catalina 310 Quincy, MA
What is your setup now, Ken? Separate house and start batteries? What exactly is the "hit or miss" starting issue? How would an additional start relay help?
 

NYSail

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Jan 6, 2006
2,585
Beneteau 423 Mt. Sinai, NY
I forgot how but it was quite simple. Bought a relay from the automotive shop and worked perfectly. Very easy...... pretty sure a schematic comes with relay.

Good luck
Greg
 
May 27, 2004
1,518
Hunter 30_74-83 Ponce Inlet FL
Perhaps the start button on that "B" panel of yours (like mine) is un-cranky at times!
 
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SG

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Feb 11, 2017
1,670
J/Boat J/160 Annapolis
It's not usually the switch or the battery.

The issue is that if there is a relatively small voltage drop along the wiring, the solenoid won't trip. The relay is interposed and will give you much more reliable voltage almost directly from the battery to the starter solenoid.

We did this for our Yanmar 16 years ago. -- it solved that problem of "the Sound of Silence" that I came to dread. ;^)))
 
Aug 7, 2018
132
Catalina 350 Great Sodus Bay, Lake Ontario
Our O'day 34 purchased last year will sometimes "click" when using key several time before it starts. No problems with battery, tested fine. The boat broker told us that was "nomal" It doesn't sound normal. Will a starting relay fix that?
 
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Nov 6, 2006
8,823
Hunter 34 Mandeville Louisiana
This from Claude Auger .. The "start" wire goes to the low current side of the relay then to ground.. A hot wire from the big hot terminal on the solenoid goes to the high current side of the relay then to the small terminal that the "start" wire used to go through.. The concept is that the relay feeds the "start" terminal with very short wires with almost no voltage drop .. the relay works from the old long, high voltage drop wire from the start switch..
Yanmar Starter Fix.jpg
 
Feb 6, 1998
11,284
Canadian Sailcraft 36T Casco Bay, ME
The problem with many marine engines is the path between the battery>engine panel>solenoid. Too much voltage drop, usually due to corrosion or poor terminations, causes the voltage to be too low to pull-in the solenoid at the starter motor. Wiring in a "Start-Aid" relay bypasses the corroded wiring and often the old solenoid wire can now be used to simply excite the start-aid relay coil. This takes a lot a bit less amperage than pulling in the large starter solenoid..

The best option is usually to clean up the terminations and wiring issues but many choose to go with the relay instead.

Any decent relay will work from cube-style to an automotive phenolic or metal type like below. The diagram below uses a "Ford-Style" solenoid...

 

HMT2

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Mar 20, 2014
822
Hunter 31 Shoreacres, TX
Before you go to all that trouble, I had the same issue with my Yanmar 2GM. I was thinking of doing your repair, or running a wire directly from the start button to the existing starter solenoid. As a last ditch effort I removed the two connections on my starter solenoid, sanded them with 220 sand paper, wiped them down reconnected them and hit them with an elctronic corrosion inhibitor. It now starts the first time every time for about two months now. Just a thought.
 
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RoyS

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Jun 3, 2012
802
Hunter 33 Steamboat Wharf, Hull, MA
Daviddp, Yes, the relay will fix your problem. Some of us first replaced the start button, then the starter solenoid, then the battery, and found no relief. Eventually some of us installed a new larger wire bypassing the original harness plug connectors and found relief, at last. Either way, you must overcome the voltage drop to the starter solenoid.
 
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Jan 1, 2006
5,163
Slickcraft 26 Greenport, NY
I cringe at the sums of money that have been spent on this problem to no gain. Please follow MS's advice, or the advice of others to run heavier wiring to bypass the harness. For my 356 with a Yammie 3gm I considered replacing the harnesses, but I could not follow or understand what all the wiring was. Not to mention the harnesses are expensive and by experience not big enough for the task. So one of the alternative solutions, the relay, gave me relief. I can't imagine there is a boatyard that doesn't know this, and yet batteries are replaced, starter buttons are replaced and when all that doesn't work, there is a shrug and a "Talk to the boss..."
 
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May 7, 2012
807
Hunter e33 Maple Bay, BC
Please follow MS's advice, or the advice of others to run heavier wiring to bypass the harness.
+1

I installed a Cole Hersee relay earlier this year. The wire from the solenoid to the start button was 16 AWG in my Hunter 33. I figured the total round trip for the start circuit including through the neutral safety switch was nearing 40 ft. That is a long distance for that gauge wire to carry all but a small amount of current. I could not find the specifications for the Yanmar/Hitachi starter solenoid anywhere on the internet. So I measured the solenoid coil resistance and found that to be less than an ohm (0.5). Keep in mind that at extreme ranges VOMs accuracy can be suspect. I measured the current necessary to energize the solenoid and found that to peak at >19.99A which is the maximum my meter can measure. This is consistent with ohms law (12Volts/0.5 ohms = 24 Amps). I also found that the voltage when measured at the solenoid was 8.75V, a huge voltage drop. I ended up putting the Cole Hersee relay in the solenoid control line with a coil resistance of 17.5 ohm, thus less than 0.7A. This makes me a whole bunch more comfortable with the control wire sizing I have. The 12V across the contacts of this relay, of course, now feeds the starter solenoid.
 
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May 20, 2016
2,943
Catalina 36 MK1 94 Everett, WA
I think the amount of current required on the solenoid is vastly in appreciated on many small motors. We think it’s only a solenoid so a few amps at most. The report sheet on my Bosch starter for the M25 reported that it took 31amps to push the bending into place and 10 amps to hold it there. That a lot of current if even for a short duration. Upping the wire gauge will help, but the switches are typically rated at 7 amps with the better ones at 20 Amps. The response from the starter was 100% better after installing a simple 60/40 relay. Plus I’m not sending all that current down and back 30’.

Les
 

SG

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Feb 11, 2017
1,670
J/Boat J/160 Annapolis
The relay is usually very successful because it is the"tripping" power that comes through the key switch or button in the cockpit. The relay takes (say) anything above 11.8 volts to connect a much shorted and clean lined from the starter battery ( or whatever). That shorter, heavier gauge source will be at close to the battery voltage. The solenoid needs something (as memory serves) of 12 volts and a bunch of amps. You can spend a bit of money and time with a variety of another approaches.

I agree that I am appalled at the number of yards that cycle a lot of $'s and don't fix the problem.
 
Oct 29, 2005
2,094
Hunter Marine 326 303 Singapore
MS, I suppose the "I" in your drawing goes to ground/negative?
 
Feb 6, 1998
11,284
Canadian Sailcraft 36T Casco Bay, ME
That particular relay, is what is commonly referred to as a "Ford Type", has the coil internally grounded to the mounting ear hence the black line from the ear to the batt neg. A Ford type relay has an "S" & "I" terminal. "S" is your coil excite. The "I" terminals is not used.

Relays that are sold as "isolated" or "insulated ground", such as a Cole-Hersee 24059 etc. would use one small stud for B+ and one small stud for B-. A relay such as the Cole-Hersee 24037 has one small stud and internally grounds the relay coil to the case/mounting ear.... It really just depends on which relay you decide on.

The Cole-Hersee 24037 is easier to use as it only has three terminals on it and these are a very good quality relay/solenoid. The only reason I drew that diagram with the Ford type was because of the head on view of the relay... Any relay can work, but the wiring of the relay coil will need to be confirmed.
 
Feb 6, 1998
11,284
Canadian Sailcraft 36T Casco Bay, ME
I think the amount of current required on the solenoid is vastly in appreciated on many small motors. We think it’s only a solenoid so a few amps at most. The report sheet on my Bosch starter for the M25 reported that it took 31amps to push the bending into place and 10 amps to hold it there. That a lot of current if even for a short duration. Upping the wire gauge will help, but the switches are typically rated at 7 amps with the better ones at 20 Amps. The response from the starter was 100% better after installing a simple 60/40 relay. Plus I’m not sending all that current down and back 30’.

Les
I see an average of between 8A and 18A on most starter solenoids for sailboat AUX engines. We have a 1kW starter on the re-build bench right now that pulls 17.4A at 12.1V. Unlike the starter motor itself, the solenoid does not really have any in-rush to speak of.

By the time you pass through 15' plus of small gauge wire, often 12GA to 16GA, a neutral safety switch, a starter-switch, fuses, terminations & the related corrosion, the voltage to the solenoid can be quite low and often not enough to do much.

The engine manufacturers often design for near "ideal" conditions but the marine environment is far from ideal.. Yanmar in-particular, has used various size wire for the starter solenoid, depending upon the vintage. I have seen as large as 10GA and as small as 14GA.

Something many are unaware of is that Yanmar also offered, on some engines, an optional "starter relay". Some builders opted for the starter relay configuration. Island Packet is one of those builders who ordered Yanmar engines with the optional starter relay. These factory start relays are usually located right below the starter motor bolted to the engine block. You could pay Yanmar about $80.00 for one or grab one at any auto parts store for about $15.00 to as much as $34.00 for a premium Cole-Hersee.
 
Jan 27, 2008
2,956
ODay 35 Beaufort, NC
Our O'day 34 purchased last year will sometimes "click" when using key several times
No it’s not “normal” . You will need to be a bit of a contortionist but try this first, remove and clean the terminals on the starter solenoid. Hard to get at but I have confidence that you can do it. Next there is a little cheap in line fuse in the wire going to the solenoid. Cut the wire and throw it away, replace it with a ATO/ATC waterproof fuse holder and fuse that has a sealed cover, use good butt terminals with good quality crumpets and adhesive lined heat shrink tubing to connect the new fuse. See if that does the trick. https://shop.sailboatowners.com/prod.php?352
SBO shows out of stock. Here’s another source, 10ga wire, 40A fuse for 6 bucks. https://m.delcity.net/store/ATO/ATC...MIicLLkr-43wIVBpFpCh28CA3LEAQYByABEgIUkfD_BwE
 
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May 20, 2016
2,943
Catalina 36 MK1 94 Everett, WA
@jibes138 you can cut out the fuse and toss it for all the good it does. It only protects about 3” of wire. Better yet relocate the fuse to the start switch/button & make sure power to your panel is fused. It’s amazing how many motor and switch panels have no fuse or cb between it and the batteries.
 
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