1. if motor starts in 4 seconds with one battery you are great.
2. if it takes two batteries to start in four seconds ... that is a sign that something is wrong or about to get worse.
3. with batteries every time you flip a switch the voltage will drop ... depends on how much you are drawing how much the voltage will drop. I have yet to get the same voltage on the master fuse panel that is available at the battery ... do this test if you have a voltage readout on your gps ... see if it comes anywhere near the voltage you read at the battery.
4. on larger boats they often have a bypass pushbutton switch in parallel to the starter button to basically do what you are doing with a screwdriver. That is generally near the motor access so you can easily start the motor at the motor. The ignition still must be turned on before you start.
5. I am waiting for this winter for Bill to give me an analysis on Vee Jay 505's original starter ... that Hitachi starter took me though all the steps last winter and finally was resolved with a cheap chinese replacement starter via Ebay (new). Now one season old and doing fine. Probably not "marine" grade ... but cheap.
6. anything with an in line glass fuse is a weak link.
7. Analog voltage meters are near worthless on a boat.
8. Standard marine ignition switch works fine. no special Yanmar wizardry in that piece except that it mechanically fits into the hole better. and you get a real key with the non Yanmar switch.

Basically when the motor is “cold” , sitting in the berth with the batteries on charge (also have an intelligent charger) it will fire right up…..much as it did first time today.

Motor out, anchor for a 3-4 hours and turn the key and it is dead. Jump it from the screwdriver and it fires up right up. I had a quick look at the motor when I jumped it tonight…definitely the inline fuse connector looks old and in need of replacement. The blue cylinder it hooks up to before hitting the solenoid also looks like it needs new connectors as well. I checked the motor block ground and it also could be filed and cleaned up a bit.

When I replaced the ignition switch I noticed that the fuse holder on that end also was on the tired side. I have a fair bit of incline connectors and connections to replace not to mention I will also install new batteries as well. Hopefully that solves the problem and if not then I will go after the solenoid…..Appreciate everyone’s input on this….

A couple of quick questions…

Is having a large capacitor wired in between your solenoid and starter a common item (modification?)

And secondly has anyone had any good luck with a particular battery replacement recommendation?

Many Thanks….

Battery Rec - I used to buy various "higher end" batteries but recently started buying the WalMart deep-cycle house brand at the advice of a friend.

I guess the idea is that you might be replacing them a bit more often, but they cost way less.

So far so good 1.5 years in...

-djm

All I can think of for the capacitor use is to stop a high voltage arc and prevent burning contacts when the starter button is released. From EE terms it minimizes the dI/dt (change in current over change in time). Kind of like the old condenser across the points in a distributor on gas engines before electronic ignition. The capacitor should do nothing to help or hurt starting performance.

I haven't seen a Yanmar with a capacitor there. It's not shown in any of the service manual prints.

I'm on my 3rd year with a Walmart Group 24 set of car batteries 650 cranking amps that were $70 each when I bought them. No problems.

Thanks for the responses, much appreciated. I pulled the inline fuse connector last night (it definitely looks in need of replacement) and noticed the big blue capacitor and thought hmmmmm……

On the battery front it sounds like using both of the same type of battery is common as opposed to using on starting battery and one deep cycle for acc.

On a lot of newer boats I've seen, they have gone to a smaller pure starting battery and a larger single house battery - with a battery isolator in place so that:

-both batteries charge when engine is running
-you never mess with your battery switch (unless you for some reason need to start with the house battery)
-your starter battery never gets discharged cause you fell asleep with the lights on

I've thought about switching to this method - problem I see is our nice molded-in battery trays which are not going to easily accommodate different sized batteries, leaving some compromises.

Cost on the isolator is not insignificant either.

The J/30 original installation uses a battery switch that does battery 1, battery 2 or both. I use a very complicated algorithm to determine which battery to use. If it is an odd day, I leave the battery switch on 1 after the engine is shut down. If it is an even day, I leave the battery switch on 2 after the engine is shut down. This evenly uses the batteries over their life. I start the engine on both batteries, leave it there while running to charge both, and periodically will start on just 1 battery to see how it is working.

So what works for me is two of the same type battery. Some do a battery with high cranking amps for starting, and a second deep cycle battery for the house loads. Depending how you plan on using your boat, this may be a more preferred alternative. When I've done overnight deliveries, I just start the engine and top off the batteries after 6 hours running the navigation lights - that's the biggest current draw. The instruments are negligible compared to the lighting.

There are aftermarket voltage regulator and charging circuits that negate the requirement to use the battery switch for battery selection and charging like the Blue Sea Systems Automatic Charging Relay.

Probably way more info than you were looking for

That was all good information.


I am going to clean all of my battery terminals and replace the batteries as a short term fix (hopefully that fixes the problem) and in the off season start some re-wiring projects. I’ll keep posting my results too see what ultimately solved the problem.

I most recently discovered that leaving the batteries off the charger meant they could not start the motor even at the dock…thus the batteries might be cooked…..they are old and have always been plugged in so I suspect it is time for a change….new batteries on the way….although I will do a load test tonight first….

I think an isolator will be an offseason proejct as well. Thanks for the reminder....