Which boat for our needs?

[jkust]

Sounds like a nice vintage boat. Hopefully it all works out once you give it a few shakedowns.

 

[Toto7SC]

So, The boat is at the upholstery shop to get the bimini top added and we just went shopping to get everything from life vests to flares and lord knows what. The three questions I am still not sure about are:

1. What kind of oil should I use for the 5.7 Mercruiser and do I need to replace the oil when it's low or just top it off?

2. What battery would be the best? I just bought a Minnkota dual bank charger and plan on having one designated battery in the boat and one spare. Should I also get a battery jumper or would that be overkill?

3. I always buy used cars and now a used boat, but once they are mine I treat them like they are brand new. So here is my question. Should I only put in 93 Non-ethanol gas and what should I use if that is not available. Is lower octane with no ethanol better or a higher octane with ethanol?

Thank you

 

[Maclin]

The engine only requires 87. All in All, the 87 stuff is all you need for that engine, ethanol or no.

If you read from the sources, you can find interesting points about Ethanol and octane. Regarding 10% Ethanol compared with Ethanol-Free, Ethanol provides "extra" octane, meaning the 87 rating is puffed up some by the ethanol in the mix, so the raw gasoline may not be quite 87. If the fuel gets stagnant and just sits for a year or two the, maybe sooner, and the stuff separates then the octane rating for what is left is lower. This is why some get the higher octane in the 10% Ethanol fuel. I am not sure how much a 10% Ethanol mix affects the octane, but if you keep the fuel stabilized and it gets used and replenished regularly this will not be a problem with 10% ethanol. The 87 rated stuff should be good. You can use the higher rating but it is not needed, and can (rarely) cause some spark plug deposit issues.

I have Ethanol free available to me, about a 35 mile trip one way. I have always used non-Ethanol in my boats, started back when the Ethanol thing had not happened yet. Now I am just superstitious. I was in smaller communities when it did happen, and there were always non-ethanol stations around due to farming influence I guess. I have a bunch of jerry cans that I fill occasionally and add in the boat tank as needed. Every once in a while after a boating day I pull the boat on up there and fill it. The lake I go to most is almost halfway to that station already. I always add Sta-Bil or other agent for each fill, whether in the individual cans or the boat tank.

There, my OCD confession is over.

 

[JASinIL2006]

Mercruiser recommends 20W-40 and the oil should be changed annually (many of us do it as part of putting the boat away for winter). Of course, top it off if the dipstick indicates you are low.

A marine starting battery is good, usually a group 24. I have a separate battery that I use for non-starting purposes (electronics, etc.), so that serves as my backup. It wouldn't hurt to have a starter pack, but that seems a bit excessive to me.

Your engine will run fine on 87 octane ethanol-treated gas. I don't think there anything to be gained with higher-octane fuel, but it won't hurt anything. Personally, I don't find the additional cost of non-ethanol gas to be justified, so I never bother. If your fuel system has never had ethanol-treated gas in it (which seems unlikely in 2017), running ethanol gas could dislodge crud in the fuel system and/or cause problem with rubber parts in the fuel system. Again, it's pretty unlikely that would be the case, but you could maybe ask the previous owner if they used ethanol-treated gas.

Hope this helps!

 

[Old Ironmaker]

All my fishing buddies have "booster pacs" on their boats as a back up, we fish big water on the Great Lakes. They are small enough now to fit in the glove box. They also have USB ports to charge a deal cell phone. Another back up to a VHF radio. I was the kid driving around without a spare tire and a jack. Now I have learned my lesson with contingency plans up the yazoo. I've learned my lesson.