HondaCRX

does any one know how to convert an engine from an echo srm 2501 trimmer? and the carb was obliterated by the origional owner, what walbro carb should I replace it with?[sm=confused.gif]

bn120

My Feedback: (1)

I would get a walbro wt 499 carb for it so you can run gas or methanol.

Darin

HondaCRX

methanol huh? say i have some racing kart methanol could i mix it with the same gas oil ratio as gasoline???

P.S. um...what gas oil ratio DO you use on an Echo, 32:1?

bn120

My Feedback: (1)

methanol is not made from a petrolium based product so it has no inherent lubrication so you do need a little more oil about 25-1 is good ,and you can use it in gas engines just fine but alot of time you need to open up the jets to meter methanol but the wt-499 is good for both gas and methanol,if you have the cart methanol use it it puts out alot more poop but takes more fuel.

Darin

ps all my small gasers are now glow just get the spark plug adapter for a glow plug $10.00 and the carb from ch ignition.

Volfy

My Feedback: (23)

That and the fact that methanol is single fraction, which means that when it evaporates, it's all gone. Gasoline is multi-fraction and so when the volatiles vapor off, the heavier fractions remain to offer a bit of lubricity.

However, all this is offset by the lower stochiometric, or ideal air-fuel mixture, ratio of methanol. This means that per induction cycle, more fuel (and thus more oil) enters the crankcase than if run on gasoline. I would say 4 or 5 Oz per gal, or 32:1 or 25:1 are okay. I've heard of people running 40:1 with apparently no ill effect. I've always just added about 5 Oz. castor per gal, and a few Oz of nitro for better transition and easier needle tuning.

Volfy

My Feedback: (23)

BTW, didn't mean to sway you towards a glow conversion. Echos are great engines and a cut above the Ryobis and Homelites in terms of build quality and power-to-weight ratio. Yours is a 24.4cc engine and should be a great runner. You'll find that it weighs quite a bit less than other "homeowner grade" 25cc weedies. I have an Echo 25.4cc converted to CH Synchrospark ignition. I also use a WT-499 carb, but I run it on gasoline. I would do another Echo conversion in a heartneat, if I can find another one cheap. Tough to find Echos for less than $150. I am waiting till around Xmas to go pay the local Echo service shops a visit. They tend to have used weedies and chainsaw available in the off-season.

Good luck.

mikenlapaz

What is the venturi size on the WT-499-1 (not shown Walbro site)?
Is it just the needle valve design of this particular carb that makes it a good canidate
for methanol? Any special considerations as to type of diaphram of other interior parts?

HondaCRX

i got mie from a freind who works at the fire station. theres a dumpster outside and mower-men are always dumping them there. he usually gives them to his dad who loves fixing those engines, so i asked him to find me an echo(reliability). it came with 2 carbs, one broken plastic POS.and a metal one missing the primer bulb and some other weed wacker parts that are total trash. but the engine looks as if it will clean up nicely!

bn120

My Feedback: (1)

I am not sure on the bore of the carb but it is big enough for a 35cc,it is alot bigger than the stock carb.

Darin

Volfy

My Feedback: (23)

WT-499 is 11.11mm, which is shown in Walbro's website. You just have to know of a particular application for the carb in order to get to a link that shows the venturi size.

For example:

http://wem.walbro.com/walbro/product...lyName=KOMATSU ZENOAH/REDMAX

Volfy

My Feedback: (23)

Use with methanol has more to do with the fuel passage diameter than the venturi size. If you already have a good carb, there is no reason to buy a WT-499 just to run methanol. You can get Ralph (RCIGN) to modify your carb for you. I buy WT-499s most because my weedies either came with useless fixed jet carbs or as short blocks alone with nothing on it.

Volfy

My Feedback: (23)

Here's my Echo 25.4cc converted with CH Synchrospark ignition. Notice the letter "E" cast on the front of the cylinder base. I assume this denotes an Echo engine. I have no idea which weedie it came from, only that it's a 25.4cc and twin ring. Much lighter engine than the Homelite 25cc.

Volfy

My Feedback: (23)

For comparison, here's a very similar 25cc dual counterweight weedie. This one came from a Cub Cadet CC-2000 weedie. I originally thought it is made by Kioritz, but judging from the fact a Zenoah flywheel fits perfectly and the rear case bolt pattern matches the holes on the G-23 mounting plate, it's probably made by Komatsu/Zenoah. It's a single ring though. If anybody know what the letters "KDC" cast on the cylinder might stand for, pleast let me know.

I've been eyeing the Toro 25cc weedies at Home Depot and wondering who makes those. That'll probably be my next fun project. I love these little 25cc jewels.

Oh, got to give credit where credit is due. Terry Grant at CH installed the ignition kit on both of these conversions and test ran them for me. Thanks Terry.

HondaCRX

WOW thats WAY cleaner than my engine![sm=stupid.gif] guess i need to clean mine huh?

HondaCRX

and heres the strange wy carb(not actual pic)

mikenlapaz

Those are both very nicely detailed enginges. particularly like the FH allen mount screws. The detail on the CH sensor also has my curiousity about what's hidden behind the prop hub.

Volfy

My Feedback: (23)

All they are is a hall effect sensor epoxied on the end of those aluminum tabs. The sensor picks off of a magnet, which is pressed into the back face of the flywheel/prop hub. I like this arrangement better than a magnet pressed in on the circumference of the flywheel.

maik

I did a conversion on a 21cc echo that i got from a surplus shop. 800 pesos roughly 40 bucks

Mounted it on a 62 inch fun fly

If you send me your email address i can show you.

I'm having trouble posting em in the threads.