Hello everyone. I got an os .91 engine and have been having a difficult time getting the electric starter to spin the prop fast enough to get it started. I have been using a new(2 month old) Hobbico battery and have a new standard starter that works just fine with an os.61 that I have. I believe the battery is getting a good charge and holding it. When the engine does start it runs like a top.

I have no idea when an engine gets large enough to need another starting procedure. The largest engine I have any experience with is a .61.

Motorcycle battery, car battery, something wrong with engine (compression feels "good" to me)? etc etc etc

Thank you for your help.

Steve</p>

Pick up a lawn mower battery from Wal-mart (~$19). That will give you the "oomph" you need to start it.

Ken

Pick up one of these for 10 bucks and you will not have any more wimpy starter woes!

http://www.harborfreight.com/18-volt-battery-67029.html


Just crimp on a couple of blade conectors on your starter cable and you are good to go. I do a simple mod and go full portable.

John

I agree with John and Ken, I bought a new 12v battery for my box and I trickle charge it every winter. So far it gives me enough power to crank over my O.S.91FX- Ringed for the past 2 years. I think my battery is over 5 years old now?

Tower sells them and so does Horizon. But you can save a few bucks and buy a lawnmower 12v battery instead. I've seen It work.


Pete

I use an 11.1 V Lipo for my smaller engines. This also starts my OS.91 FX.

For bigger engines I will opt for a 14.8V Lipo (high discharge type, you need amps).


check he amperage your battery is delivering. It could be old and still charges to correct voltage but is not delivering the amps

If you want to start your motor successfully, this will do it, http://www3.towerhobbies.com/cgi-bin...&I=LXFT88&P=ML . The "standard" starters often don't have the "oomph" you need for the larger four-strokes.

The important equation to remember is that power of the starter motor is proportional to the voltage squared that is at the input to the starter. The other thing is to know is the internal impedance of the battery source subtracts voltage applied to the starter based on the current that the motor is using. The lower the internal battery impedance, the better.

Yup yup and yup 18V/1.3Ah Nicd Gentlemen do not dismiss this ten dollar battery or you will be missing out.

http://www.harborfreight.com/18-volt-battery-67029.html


John

Use the biggest rubber spinner adapter you can fit on your starter and spinner cone - helps a lot.

Lipos are the way to go. Hobbico battery is terrible.

John, what are you using to charge the beast?? Is that one of the replacement batteries that Harbor Freight sells?? Or is it mail order only??
Gene

GB I don,t know wheather or not your local Harbor Freight store in Henderson sells them at that price or not.

Definately worth a local call.

I ordered two at that price on the net and if I am not mistaken I think the shipping was about eight dollars.

I think many of the newer generation of chargers with automatic voltage sensing and a selectable charge rate will charge it fine. I use one of these actually I have two of the yellow ones and the red one is a no name from hobby king that I paid fifty bucks for (threw it in with some elses order).

I use a sensible C10 rate, well just over anyway since charger won't go to 130mah charge rate I just us 200 mah or .2 ah

Seeing more an more of the fellows with Red battery packs on their starters these days.

John

Thanks John, I will give them a call this week. I use an auto jump starter and hook it up to both my starter and flight box but miss my cordless starter system. The little 7amp flight box batteries are OK when new but tend to need replacing every year and don't have the zing I need for most of my glow engines. MED, most any of the cheap starters should be able to roll over a .91. As I mentioned, the little flight box batteries you buy from tower or a hobby shop work fine when new but loose there poop too fast and the starter bogs down. More voltage really gives any starter a zing but you don't want to be rolling over an engine too long or you can feel the starter when it begins over heating. My auto jump starter is great but it's still only 12 volts, it lasts forever though and I have even used it to jump start guys trucks at the field. I do like cordless though and 18 volts is better then 12. I have been able to start some of the small gas engines with my standard starter and 12 volts, most of my own glow engines are 1.20 and they present no problems, a .91 the starter doesn't even know it's there. This is a low end starter too, something cheap I bought at Hobby People, I think it was $20.00 on sale, no need for the big starters if you have a good battery.

I use a Optima Red top car battery because it has a handle on it!

I like it because it really take very little to pick it up (has that nifty handle) and put it in the back of truck. I use it to charge my RX TX battery's and start my planes.

I really like the fact I only have to trickle charge it once every 2 months!

And I really really like the fact that the Optima will let my Hobby Shack $29 starter fire up my Zenoah engines.

Oh Ya, remember to turn the prop clockwise to the "back" of the compression stroke to give your starter a running start.

Turning the prop backwards until it hits compression and then spinning up your starter before jamming it onto the spinner will help a weak starter get an engine going. Makes a ring on your spinner after a while though.

I see people spinning up there starters then jamming them onto the spinner quite often. It's something that shouldn't be done at all. The prop should just be rotated clock wise until the piston is at the top of the stroke then the starter placed on the spinner then hit the starter button. I have seen a few flooded engines end up with bent rods when the starter is spinning then put onto the spinner. Usually the spinner screw breaks first but it's not something to count on.

Boy i sure do agree with GB on that. Of course forgeting to back up the prop is a common mistake and often with a four stroke ya sometime have to back them up two full revolutions.

But ya know every time I see someone treating an engine and airplane like that by triggering and then slamming a starter it just tears me up, Gentlemen that is no way to treat your engine and it is no way to treat your airplane.

One of the more comical incidents I was witness to not very long ago (it was comical only because no one was hurt) occured because of a gentleman who insisted in using this destructive technique.

He was using one of those wimpy 12volt portables and some sort of fourstroke and he insisted on slamming the starter. Well sure enough at one point it fired, there was a loud cracking noise the engine now running departed the airplane with the firewall and the fuel tank following close behind. Needless to say he never angine used that so called technique.

John

John

Glad that I took the advise that you gave on this topic. I took your advice and purchased the battery from Harbor Freight. I used it for the first time the other day and works like a champ. I had to use it to get my 26CC gasser started. Little Hobico 90 starter will turn it now. Only difference is that I made an adapter to hold the battery in place; locks in with the battery tabs (see pics).

I had Hobico's power pack on it before this. The battery was going bad and figured I would try this. Cost less than a replacement battery from Tower. Thanks

I don't use the bump technique much but I have been known to do it at the end of a flying day when the batteries on my starter are low. It's an option in a pinch and will only cause damage if you don't hit the spinner straight.

Can't believe no one has suggested loosening the glow plug to start engine. I have had to do this on 1/10 scale cars using a "bump box" starter. Once engine starts, tighten down the plug.

[slaps forehead]</p>

Thanks RCF, yes since that battery has been out it has pretty much dominated at our field and you look down the line it is rare to not see starters without a red battery anymore and even more unusual thank heavens to see one plugged into a power panel.

FP that type of table starter puts an entirely different type of load on the engine. It is ninety degrees to the side of the axis of rotation not in line with the axis where there are no berings to take the load or bumps.

Yes I confess I also have used that technique before in a bind as Jester indicates but it is not really something I care to recommend.

Hmm, FP loosening the glow plug, Don,t think I'd care to try that one but it sure reminds me of an old motorcycle I loved years ago that had a compression release that you pulled for kicking that big old single over. it actuated a mechanism to open the exhaust valve a bit. Sure loved that old AJS.

John

Befor electric starters, we used to prime the engine WELL, then attach glow starter and flip the prop backwards (yes backwards) from no compression toward compression. As soon as the piston had developed enough compression to fire, it would; before top dead center, driving the piston down in the proper direction, and the engine would start and run. Used to drive the people at the field crazy.

Les

I measured and found that my Tower Hobbies starter draws about 15 amps starting my Saito 100. With this much current, good wire and good connections are important and can make a significant difference in the power of the starter.

Also, in colder weather (I notice the OP is in Iowa) the 1.2 V glow sticks don't work so well. Glow plugs are designed for 1.5 V. We get away with 1.2 V, but this becomes more of a problem at lower temperatures. In the winter my engines start more easily from a power panel.

John, I love that idea. But what do you charge this battery with? Can 18 volt chargers be purchased?

JP see my post #11. Virtually any of the new auto voltage sensing chargers with varible charging currents do just fine and you don,t have to do anything special, I just use a normal C10 overnight rate.

I use three of the inexpensive chargers in that picture for all the airplane charging, the ni-starters and now the 18v starters.

John