RE: Poulan 25 from FL trimmer
 

I run the en\gine again (glow plug powered all the time, 93 Chevron gasoline mixed 1:30 with Motul oil - no methanol added). The engne run very stable 7400 rpm max (MA 16x8 Clasic) idling at 1600 rpm with very good transition. After a couple minutes it started to miss and eventually died. Then I couldn't start it again. I thought the glow plug went bed so I checked it. I found glow plug still in excellent shape but was not glowing orange, but rather dark red. The reason - glow battery died on me. I put a new battery and everything went to normal. Engine started after a few turns and run like usuall. I run it for another couple minutes without any problems.

Conclusion:
1. After total 20 minutes of runing I didn't notice any wear on engine nor glow plug.
2. Current on the glow really doesn't matter. Engine fires when it wants to, but at least my Poulan 25 wants to fire at the right time.
3. When glow plug is to cold engine just dies.

I'm not going to abuse (test) my engine any more, as I need it as it is (magneto ignition) for the plane I'm building. However I just bought another Poulan 25cc. This one I will cut to the bones making it as light as possible removing also magneto support and flywheel. Then I will test it as gasoline glow engine for longer time. If it works well, I will have the lightest gasoline setup ever: about 2.5 lb 25cc engine (including muffler, mount and on-board glow) runnign from 10cc fuel tank. Any 'brand name' of that size weights at least half pound more (and costs 10 times more ). For comparision the MVVS 1.6 I have weights 33 oz plus 5 oz muffler, + 2 oz radial mount plus 5 oz ignition plus 3 oz battery. = total 48 oz. It was the lightest gas setup I could ever come with so far.

RysiuM

RE: Poulan 25 from FL trimmer
 

RysiuM
Which glow plug are you using? Read about using 4 Stroke plug in another thread.
Where is the glow element in relation to the bottom of the metal (Alum) plug you inserted in the old spark plug?

RE: Poulan 25 from FL trimmer
 

I must admit, I have no idea. It is not OS A3 (I have whole bunch of them), and looks like the other K&B plugs I have (KB-1L). I get it from the box I keep 'no good' plugs (It didn't not hold glow engines any more - like platinium is gone).

I made an aluminum insert pressed inside the demolished spark plug so the bottom of insert is flush with the spark plug bottom (I cut off the elctrode flush with the bottom of the plug). Then the glow plug is flush with this (it does not stick out of the spark plug).

RysiuM

RE: Poulan 25 from FL trimmer
 

Finally I have some comparision numbers to brand name RC engine. I run the same wooden prop 18x8 I had on MVVS 1.6 gasser. This prop is way to big anyway. But my MVVS (new not broken yet) turned 6700rpm and after opening the muffler it peeked at 7000rpm. Poulan 25cc couldn't go beyong 5400rpm. It is over 1300rpm less.
I was expecting this as I could easy feel Poulan has much lower compression than MVVS 1.6. But what the heck, if you are not into super high performance and want to save a buck, this conversion is fine.

RysiuM

RE: Poulan 25 from FL trimmer
 

Hi,
I bet that your MVVS won't run well with a glow and gas fuel. Hows that for low weight and cheap fuel?

Dave

RE: Poulan 25 from FL trimmer
 

I'm sure it doesn't. Do much compression.

And for cheap engine. MVVS cost me 10 times more than this weedwacker (or 20 times if I don't include muffler).

Every day with every new experiment brings new eperience and gives me more knowledge. But unlike many other guys I don't keep them in secret. I have this luxury to take is as a hobby and because I don't do engines for living I can let the secrets out :D

I have another Poulan 25 on it's way so I will check is it behaves on the glow plug the same way. I'm going to make it super light gas fuel glow plug engine and put it on some 3D frame. Than I will see if it behaves.;)

RysiuM

RE: Poulan 25 from FL trimmer
 

Hi Rysium! this is areo nut from the gas fuel glow plug no ignition, where did you buy the engine at $25 bucks' I am currently flying a 25 featherlite plus with 50%gasoline, 50% methanol and 5% nitro and having a ball with it, better rpm's than gasoline , smoother and better transition from idle to high, so I would like to buy a couple more to convert and design a plane specially for that engine, I am currently flying a ModelTech Excite 90 and cand do everything with it, but it seem that they aren't selling that plane any more, or at least Hobby People isn't.
So please I would appreciate if you can give the addres on where to buy the engines if they still have them available. Thanks.
Your buddy from down Baja. Bill Pomplun A.K.A. Aero Nut.

RE: Poulan 25 from FL trimmer
 

Hi Bill,

There is a Store on E-bay that belongs to [link=http://stores.ebay.com/ThePlace-Nashville_W0QQssPageNameZviQ3asibQ3astoreviewQQtZk m]theplacenashvill[/link] - very nice and friendly people. Look for 25CC WEEDEATER ENGINE REPLACEMENT for $22.5 on auction ($25 on Buy it now) plus $10 shipping in USA. The catch is, thay can't ship to California (that stupid emission law). I don't know about Mexico. You need to e-mail them.

Richard.

RE: Poulan 25 from FL trimmer
 

For what it's worth, I have one listed on eBay #5986718199 that has the larger ports and the bolt on exhaust. It's from a leaf blower and should be an easy conversion. I can ship to California!....Bob

RE: Poulan 25 from FL trimmer
 

How much with shipping

RE: Poulan 25 from FL trimmer
 

Hi again! If you are really interested in this engine you would have to win it through ebay. It ends next Sunday. These are light engines and the shipping would probally be $10 or less most anywhere on the continent. I feel a little funny about jumping in and selling something through these forums. Mostly I just moniter and have learned a great deal over the time I have been a participant. I do sell a lot of engines of various types on ebay and have been doing it for about 3 years. At any rate if you email me I am always ready to answer questions and so forth..........farley9n

RE: Poulan 25 from FL trimmer
 

Aero Nut,
Here is the address for the exact engine our buddy used. http://cgi.ebay.com/ws/eBayISAPI.dll...986202297&rd=1
I think that lower compression and smaller ports actually help gas/glow performance.

Dave

RE: Poulan 25 from FL trimmer
 

Check Sears for discontinued or reconditioned weedeater 25cc featherlite string trimmers. I bought one today for $55.00 in like new condition. dave

RE: Poulan 25 from FL trimmer
 

I looked at the whole line of FL trimmers. There are many version of 25cc and some of them are allowed in California. I believe they are a little more restrictive for the power so it will not polute much. On the other hand, i think they will be weaker for our project. So I will stick with the enignes that are not allowed in CA for better power and performance. Hopefully our planes don't need to pass smog test yet to fly in California ;).

RysiuM

RE: Poulan 25 from FL trimmer
 

The Poulan factory store in Texas sells the FL 25cc Leafblowers for 37.50 (we purchased around 10 of these last year) and they also make great conversons. The carb adapter is twisted so it makes it very easy to hook up to the servo. It is an incredibly easy conversion I have been flying mine on a BalsaUSA Eindecker for over a year (well the eindecker plinked in a couple of weeks ago due to me trying to fly on a dead battery, but the engine is one tough little bugger). I am getting almost exactly the same stats that you are. 7200rpm on a 16x8. Its not a powerhouse by any means but for 46.50 (cost with shipping) I have a reliable engine for floater aircraft. By the way, DONT CUT OFF THE EXTRA MAGNETO BRACE. Sorry for yelling ;) If you have a hard nose landing (what? ME? Never!) you can easily crack the mag housing right off the engine. (Can you tell I have experienced this?) Some creative use of #6/32 screws and a tap fixed it up a bit.

RE: Poulan 25 from FL trimmer
 

I have two new engines comming in and I want to see how light I can go. This time I will cut every piece of the case I would think is not needed (including magneto bracket and fuel tank mount). I want to see how light this engine can be running on the glow plug. One sub C size NiMh cell (3700 mAh) that weights 2.3 oz can power the glow plug for almost 2 hours. If it works fine this could combine all benefits of gas engine (fuel economy, clean burn, reliability, no restrictions for fuel tank positioning) with benefits of glow engines (light, simple, cheap, no RF interference). I'm not going to achieve the glow engine's power but rather having a gas engine witout going into all related expenses and complexity. And 7400 on 16x8 is good enough for me as long as it cost less than 50 dollars to buy and less than a dollar for 1 hour of flying:D

Now I need to find a cheap plane that I can put this engine in.

RysiuM

RE: Poulan 25 from FL trimmer
 

I did this one just last week. Ultra Stik 60. moved the firewall back an inch and a half, put the servos in the tail, made a hatch in the rear of the fuse for the battery, used a Sullivan tailwheel. I don't know how accurate my digital fish scales are, but they say it weighs 7lbs, 10 ounces. I've got 5 flights on it so far, great flier and it still lands like a Stik. This particular motor turns an APC 16x8 at 8450rpm and gives the plane insane vertical. Looking for someone with a DA 50 to challenge to a vertical drag race out of a hover.:)

RE: Poulan 25 from FL trimmer
 

Farley9N -

I see nobody bought your engine on Ebay....wanna sell it to me. I know you said you weren't thrilled to sell stuff on this forum, but if you would entertain it, let me know what you want for it. You can email me at [email protected].

Thanks,

Scott

RE: Poulan 25 from FL trimmer
 

Hey Rysium try a 50/50 gasoline /methanol combination on your glow conversion and you will see a tremendous difference in power also you won't need the battery just try, I thi8nk that you should be able to get some methanol in your locality.

RE: Poulan 25 from FL trimmer
 

I read about all the problems mixing menhanol with gasoline and oil (I used Motul).

BTW what kind of places sell methanol? I never needed one so I have no cle where to look for it. I didn't see it Laws, Orchard nor Home Depot, so it is not a probably paint solvent. I saw 91% isopropyl in Walmart (90c for 16floz) but I don't think it will work the same.

One more thing is how my carb will survive methanol? I don't want to destroy it.

RysiuM

RE: Poulan 25 from FL trimmer
 

Methanol won't destroy the carb...We rebuild the carbs on our methanol powered race engines and fly all season...I have carbs here from about 6 years ago, just put in a box and left alone...Only thing needed is new diaphragms, the old ones get stiff..
FWIW, Walbro does NOT make any special carbs or diaphragms for methanol..The WT499 used on the glow G23 uses the exact diaphragms as all the others....You can see the official word from Walbro's engineer Luis Salas on the carb section at my website, rcignitions.com:D

RE: Poulan 25 from FL trimmer
 

I read this note and it is exactly what I'm saying. I didn't mean that methanol wil rust aluminum or brass parts;) The rubber-kind parts in the fuel pump part will stop working over the season or two.
I have a weed whacker and a blower that I'm using for last 7 years and I don't even know where is the carburator in these things:D I expect the same reliability form model airplane engine. I don't rebuild my glow engines every season and I'm not going to do with gas either.
Saying that I don't mind running glow plug from the battery during the flight. NiMh cell will last much longer than diaphragms soaked in methanol. Sub-C NiMh (3700mAh) weights a little over 2 oz, will last for at least 90 minutes on one charge, and can be charged at least 500 times. It's much easier and cheaper to replace NiMh than rebuild the carb:D

RysiuM

RE: Poulan 25 from FL trimmer
 

I agree with RCIGN1, but one thing to remember is that when you use methanol mixed with gasoline the effect over the diaphragm and pumps is totally different due to the fact that gasoline adds lubricicity to those parts and you aren't using pure methanol only; its like diluting the strenght of the effect of methanol over the rubber parts. I havent seen any damage so far on my carb and I had been using it for just about two seasons and haven't had the need to replace any parts on it.

RE: Poulan 25 from FL trimmer
 

I will give it a try. My next Poulan 25 should come today. I will cut off all aluminum parts including fuel tank mount and ignition support.
I wonder - do I need to keep a piece of flywheel (shaved to to diameter of the hub) or can crap it using hub only? With a glow plug I shoud be able to get about 2lb an engie.

If this engine weights no more than 2-1/2 lb (including glow battery, muffler and mount) and turns at least 7500 with 16 inch prop (I didn't try it with APC 18x6W yet but I think it will turn it around 7500rpm too), is it a good choice for Funtana 90?

RysiuM

RE: Poulan 25 from FL trimmer
 

Make sure you keep your speed down on the funtana 90, two at our club have had the right wing come apart in the air. One of them had a gms 120 and the other had a moki 135