Outboard motors; Cruising, dingy, tips, maint, & reviews

[AdriftAtSea]

Fortis-

I wouldn't suggest or recommend a composite prop for an inboard diesel engine.  On an outboard, it isn't the bottom-most part, most outboard motors have a skeg at the bottom of the lower unit that is the lowest part of the outboard.  I would recommend that you get a "Macs River Runner" for your dinghy's outboard.

[Fortis]

As I posted elsewhere, the most used outboard for our dinghy is the electric, which is a Mercury that comes with a nifty and guarded prop in what looks and feels like shiny black plastic, but has certainly been tough enough to cope with years of use and abuse.

The little johnson 2stroke outboard we have sees so little use that it is almost shamefull. thing is that I can get more run time out of the little tightly packed compact AGM battery we use to power the elctric then I can from the Johnson using the same volume of 2 stroke (and being able to just plug the battery in when we step on board and know that the solar panel or alternator will have it all charged up for us within a short while is kind of nice too). Power is about equivalent...give or take.

If we come to a reason to use the little 2stroke more then we will explore getting a river runner for it. Is that the long two bladed prop that is designed to cut through weeds and such?



Alex.

[starcrest]

that 2 stroke o/b would make a nice lamp post fixture in a bar room setting

[AdriftAtSea]

Alex-

A Mac's River Runner is a plate that attaches to the bottom of the outboard motor's skeg, and protects the prop from grounding.  It looks like this (the silver part at the bottom of the photo):

[Adam]

1997 6hp Evinrude Yachtwin motor. It has a "charging system" which puts out voltage. Is this safe to use to charge the battery? Or is it "unregulated" (not sure of the exact terminology here) and will it cook the battery?

The engine will be run all day for 3-4 days along the Okeechobee waterway, is it safe for the battery to be hooked up to the engine? It's NOT electric start. Just a 6hp 2-stroke that puts out voltage....

Help?   ???

Adam

[s/v Faith]

I bet the replies will be all over the board, but here is how I use mine.

  The motor does not use a alternator, or even a generator to develop the voltage, it uses a pick up and a rectifier pack to charge the battery.  Some have a crude type of voltage regulator (zeener diode) that will kinda control the voltage.

  I have mine on a switch, and I keep an eye on the voltage as the motor is running.  I usually find that it will slowly rise and I shut it off when it is around 18v.  Where there is no load, it can get much higher but it only goes higher as the battery approaches being fully charged so it won't hurt the battery.  I switch mine off to protect the radio and depth sounder from damage.

  Depending on how much current I used the night before, the batteries are usually charged in 10-15 minutes and it has never taken more then an hour.

  FWIW

[AdriftAtSea]

If it isn't regulated, then it might be wise to put a small charge controller inline with it.  The FlexCharge NC25A should do the trick and is really simple to hook up. :D

[Fortis]

ahhhhhh...very interesting indeed.

Thanks for that!



Alex.

[oded kishony]

I've been using gas stabilizers for a number of years. I have a number of both 4 cycle and 2 cycle engines that I rely on around my property ( a 4cycle rototiller, 2 cycle chain saw etc) I also add a biocide to my diesel fuel. I worry about the condition of my diesel fuel since I only burned about 2 gal in the last 2 years. Should I pump out the tank? Or should I filter it? There is a service at my marina that pumps your fuel through a special fuel filter an a nominal cost, but does this address the problems of old fuel? I try to keep the diesel tank topped up to minimize condensation. I'm interested in what other folks are doing.

oded kishony

[AdriftAtSea]

Oded-

I think that the gasoline-powered engines are going to have far more trouble than the diesel owners, especially as the percentage of ethanol creeps up.  The ethanol leaves gasoline far more vulnerable to water-absorbtion/degradation than diesel is.  Also, if the gasoline/ethanol blend absorbs enough water, the ethanol will essentially separate out from the gasoline and stop working as an octane booster.

Diesel is pretty stable, and as long as you can keep the algae that grows along the water/diesel interface in check you should probably be okay.

Dan

[CapnK]

Good thread, great info everyone. :)

Quick linkage for a couple of the products mentioned (you may find more info/better prices by searching):

Flexcharge NC25A (company site, just for product info) - and - US$115 here (retailer site).

Mac's River Runner - US$72-92

[AdriftAtSea]

Alex-

Anytime...

BTW, the Mac's River Runner is sized by the type of outboard you have. 

[BobW]

I'll share my experience with my outboard and old fuel.

A little background:

I use an old - late '70s vintage - Evinrude 6 HP on Prelude.  It was last serviced in August 2004.

Two years ago on our first trip to SF Bay, I seriously underestimated our fuel needs and only took 6 gallons of fuel.  It wasn't enough - not by a long shot.

Last year we carried 15 gallons, but, because conditions were very favorable, we used less than 3 gallons. 

Getting in and out of the marina during the year nearly used up 2 gallons.   So, when it was time to depart for the Bay this year we had about 5 gallons of fresh fuel and 10 gallons of year old stuff.

Conditions this year did not favor sailing back to the Delta, so we motored the entire 52 miles, enjoying the benefits of a flood tide for about 2/3s of the distance. 

I didn't use any stabilizers and noticed no ill effects during the trip.  I still have one full 5-gallon can of fuel that I'll use this year - I am hoping to get out of the marina more often.

I don't run the motor dry and, when I remember to use the deadman switch, the motor starts on the third pull.

I realize this is counter to conventional wisdom, but I guess there is always an exception to the rule.

[Captain Smollett]

I realize this is counter to conventional wisdom, but I guess there is always an exception to the rule.

Hi Bob, thanks for the info.  Is your area really humid?

We live in a humid area and do notice fuel age problems (mostly water absorption).  As a matter of fact, when I rebuilt the carb on my ob, I wanted to start with fresh fuel, so I emptied my old gasoline into transluscent milk jugs.  It was about 1/5 water!!

Your comments just made me wonder if some of this "conventional wisdom" is environment dependent.

[AdriftAtSea]

Capn Smollett-

I think you'll find the water-absorption related fuel problems just getting worse as the ethanol-mix gasolines become more and more common.  Not exactly a good thing for us that have gas-powered outboards as our auxiliary engines, since we often don't have to burn that much fuel during the season.. I still have most of the 12 gallons of gas I bought over last season left over.... 5+ gallons in my main tank, and 3 gallons in the reserve tank.

[BobW]

John, I wouldn't call the Delta "really humid," not like the Gulf Coast.  But it is a marine environment.  Reported humidities range from 35% to 95% (the site I use for that info is currently down).  Prelude lives in a slip and her fuel tank and extra fuel cans live in the cockpit lockers.

I don't know whether the "conventional wisdom" is environment dependent or not.  I guess we each have to understand what works for us.

[Godot]

I was reading the recent messages in the outboard thread, and it occurred to me that maybe it would be better not to run last seasons fuel in my outboard.  So, what do I do with it?

Can I pour the old gas with the two stroke oil mix in my truck?  Will it run ok?  Or do I need to find another option?

There is probably about 5 gallons of excess fuel, and my truck tank holds 15 so I'm thinking that things will dilute fairly well; but I really don't know.

[Captain Smollett]

Yes, you CAN run it in your truck.  I'd do it a little a time, maybe a gallon or so per full tank, but that's just me.

But...if it's okay to run in your truck, it is PROBABLY okay to run in your outboard.

What 'kills' ob fuel is the length of time it sits around - absorbing water and possibly evaporting volatiles.  In our cars, we usually burn through a tank of gasoline faster than that can happen.  So, it's not that the ob is necessarily more sensitve to these things than a car engine would be.

As an alternative, you could also dilute it for use in the ob.  Having made sure there is no 'standing' water (visible by separating out from the gasoline), just dilute it 2 or 3 to one with new fresh gasoline (plus oil mix).  The fuel I mentioned in that other post was WAY bad - not just a little bit, so it was unusable.  But, unless you can SEE water in the fuel, mixing it 2-3 with fresh mix should save you from having to throw it out.

My two cents....

[BobW]

I have never tried using pre-mixed fuel in my vehicle, but I know people who do just that.  They dilute it as you describe, and report no apparent ill effects.

I use a 3-gallon tank to run my outboard, and add oil to the tank when I add fuel to the tank.  I do not pre-mix my fuel in the extra cans, so maybe I could use my old fuel in my vehicle without worrying about the oil.

[AdriftAtSea]

The other problem is that the new ethanol blend gasolines tend to have much more affinity to absorbing water.  Once they absorb enough water, the ethanol/water mix tends to separate out.  The remaining gasoline is very low octane, usually about 83 or so...since the ethanol was primarily being used as an octane booster.

Burning pre-mixed two-stroke fuel in a truck engine really won't hurt it, unless you have significant amounts of water in the gas... and in the case of ethanol blends, it will be pretty obvious if that has occurred.  On some older car engines, people use additives to help clean up the valve seats and such, and most of these additives are very similiar to the oil used in two-stroke engine fuel mixtures.