Best Battery for MerCruiser 888 (1976 Ford 302)

[ratdude747]

Yes most folks are converting to PMGR for weight savings and easier install. Only issue I have heard is sometimes the PMGR is slightly shorter than the original and you need to get new bolts, which is not a bad idea anyways

It was already there when I got the boat... No audible bolt grinding (nor a loose starter) so presumably there's no issue.

If it wasn't a marine rated unit, I'd be swapping for something due to the fire hazard. But it is marine rated and I was able to fix the wiring mistake, so I seen no need to fix anything else that isn't broke in this case.

 

[ratdude747]

Got the battery tray installed:



Moved it forward a bit to match where the PO ran the old battery and to give better clearance of the manifold drain.

One issue I've run into is the studs aren't threaded enough. Bottomed out with 1/4" to go:



Probably will need to pull them and use a die to give more threads. The ends with the shortest threads are in the bottom tray, tightened until they hit fiberglass.

Battery is a bit easier to install. Fuel hoses are a pain still. I haven't figured out connector covers yet.

 

[ratdude747]

Another picture, now with stater relay mounted better (correct #12 stainless screws and plastic spacers):




Also, why the battery install is such a pain on this thing. The fuel hoses shove to the side a bit but they're generally in the way.

 

[Bondo]

Another picture, now with stater relay mounted better (correct #12 stainless screws and plastic spacers):

Also, why the battery install is such a pain on this thing. The fuel hoses shove to the side a bit but they're generally in the way.

Ayuh,..... My guess is,... The starter relay used to be mounted on the top of the motor somewhere,.....

You can find another spot in the boat for the battery, just add new longer cables,......

And, as I mentioned before, yer supposed to isolate/ cover the battery's terminals, so there's No chance of a dropped wrench causing a spark / explosion, blowing up yer boat 'n / or passengers,....

 

[Lou C]

I would also change those cables, you can see green corrosion in the strands of wire.
for insulators looky here:

Insulators - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

BTW, if you are in a coastal region, it isn't that uncommon to get pulled over by the Coast Guard for a safety check. One time they actually checked for the battery insulators!
Another time, where is your backfire flame arrestor? (they only knew outboards, I had to explain how that works on an inboard), me being a wise guy said do you wanna climb down there and read the J1171 cert on my marine starter, too? lol.
other times, they asked funny questions like
I have a couple of those bird spider things (wires in a circular pattern to keep birds off the boat) I had them lying on the back seat, they thought they were some mysterious high tech antennas. I'm not kidding. That really happened.

 

[ratdude747]

Ayuh,..... My guess is,... The starter relay used to be mounted on the top of the motor somewhere,.....

You can find another spot in the boat for the battery, just add new longer cables,......

And, as I mentioned before, yer supposed to isolate/ cover the battery's terminals, so there's No chance of a dropped wrench causing a spark / explosion, blowing up yer boat 'n / or passengers,....

The old relay is still on engine block above the starter. Currently it's just being used for a power distribution point... I can't access it very well and it was easier to mount a fresh relay somewhere easier to access.

Battery covering is a known issue I haven't gotten to yet.

Battery Location I'm fine with, as there's not a better spot. It's the biggest motor Starcraft offered in the 16' Montego... cramped is going to happen, I just need to get over it. May be a pain, but a lot less of one and after all, I did make it fit (other than the stud length, which I haven't gotten to fixing yet.

I would also change those cables, you can see green corrosion in the strands of wire.
for insulators looky here:

Insulators - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

BTW, if you are in a coastal region, it isn't that uncommon to get pulled over by the Coast Guard for a safety check. One time they actually checked for the battery insulators!
Another time, where is your backfire flame arrestor? (they only knew outboards, I had to explain how that works on an inboard), me being a wise guy said do you wanna climb down there and read the J1171 cert on my marine starter, too? lol.
other times, they asked funny questions like
I have a couple of those bird spider things (wires in a circular pattern to keep birds off the boat) I had them lying on the back seat, they thought they were some mysterious high tech antennas. I'm not kidding. That really happened.

I know the cables don't exactly look mint. If I could reach the starter and old relay better I'd swap them. That said, I've seen and worked with worse. I think they're original despite being "too long" for the original battery location.

If by coastal you mean on federal waters, yes, the coast of the Ohio River. But in terms of ocean, no, I'm in southern Indiana (Madison). Compared to what it was, it's much closer to meeting (if it doesn't already meet) federal spec:

• Originally had no flame arrestor, a 1970's Ford Superduty carb, and some very sketchy automotive fuel hose for the fuel system. I replaced with a 4 barrel Holley marine carb and appropriate flame arrestor (made for 302's, I got a deal on eBay, $400 for both)... and I replaced the fuel hose with USCG rated stuff (A1-15).
• The starter (per above) is a marine starter. Good luck seeing it (I had to hold my camera funny to get the pic).
• The starter relay is a NOS Mallory Marine relay made for a Mercruiser starter relay application.
• There are some automotive parts installed, but they're ones that either are sold as marine-applicable or to my knowledge don't need to be marine rated (at least for an old boat, not a new stock boat)
  • Intake manifold: Some sort of Edelbrock, came off the PO's project vehicle.
  • Pertronix ignition and coil (epoxy filled): marketed as marine applicable; the former is made specifically for the stock Prestolite marine distributor.
  • Oil filter: I stock Wix filters for this application (Ford FL-1A replacement, used also by both my trucks).
• At least in the Indiana boating manual the only engine equipment called out for state or federal requirement is a flame arrestor and the bilge blower. Nothing else is called out as a requirement for a used boat (I read most of the rules are for new boats, and while good ideas to follow, are not required for used boats, especially if it wasn't required when the boat was new).