I recently purchased a used model with an older OPS glow engine on it. It is swinging a 18x7 prop and is fairly large...pry a 90 or bigger...its pretty big. It also has a carb....a carb that looks like a gas carb with a high and low needle adjustment on it like a gas carb would along with a idle RPM adjustment. Now this carb is not like a normal glow carb with the long "high end" adjust....picture a zenoah carb...looks close to it...it is made for this engine...fits fine and has run before....i get it running and idling, but surges on the low end and when i give it gas it blows a little blueish smoke and dies. I dont have data on the engine and cannot find it....anyone have ideas???? How to adjust it? How many turns on the high low needles? Carb is clean and idles pretty good when cold and steadily gets worse.

I know you said glow engine but it sounds like a gas carb?
Does the engine have an ignition system?
Are you running Gasoline or Glow fuel?

All the OPS engines I just saw on the net were glow with a more conventional model engine carb

No it is a glow engine with a carb on the forward side of the head.....it was a running engine when the man died. I also found pictures of rear "carb" engines mainly referencing marine apps. It has no ignition system and a small glow plug hole in the head with a standard glow plug installed....interesting huh? It runs good on idle and at first reved up at half throttle....then i "tuned" it a little and got it off somehow and now it has the problems stated above.

Try both needles at about 2 1/2 turns if you are lost on the needles

The diaphragms may be all gummed up in the carb.

One side of the carb has a pump and the other side has a regulator

With both needles set a t 2 1/2 turns the engine idles nicely. When a quick throttle input is given the engine stays with the throttle and is very responsive. However, when you give it throttle at 1/4 to 1/2 position the engine puffs blueish smoke and dies abruptly. It starts right off again with no priming and idles good when the glow ignitor is taken off. Again, when the throttle is increased the rpm goes up to a point of 1/4 to 1/2 throttle and then the engine looses power and quits.

Did you clean the pump inlet filter yet? There's a wire mesh screen there.

it's an OPS Maxi, 30cc

Jim

Jim is correct.

A "Walbro" (copy) type Carb was offered on some of the 30 cc Maxi's. Tower sold them up until 1996 or so. I expect it should be adjusted the same way. A lot of information on care and adjusting of Walbro carbs can be found on the gas engines forum here ar RCU.

It is exactly that...a OPS Maxi 30cc....you guys are awesome. I FINALLY found a picture of one and it is what I have. Does anyone know where I can get parts for it (carb) or a manual??

It has a DelLorto 5H Carb. You may have to convert it to a Walbro?

"The factory recommends a lube percentage of between 5 and 8 percent. This is possible because of the caged roller bearings on the rod and the exaggerated fins on the cylinder and head that provide excellent heat transfer and cooling"

Also no nitro except maybe just enough to stabilize combustion.

Here's a very nice synopsis of the engine by Dave Gierke in 1998

http://findarticles.com/p/articles/m..._n8790779/pg_1

just measure the inside of the carb in millimeters, then call Walbro and ask them to recommend a crab for you, make sure you tell them you are going to burn alcohol/nitro ,

or fined another 30cc/32cc glow motor that uses a Walbro and buy a replacement carb for that motor for your Maxi..

by-the-way,, I don't know much about the Maxi, but OPS plane and boat motors are among the best motors you can buy !!

Jim

I messed with the engine a bit tonight. I tried the setting that the article suggested (5 out on the high side and 3 out on the low) and also tore the carb down and cleaned it (didn't see anything inside and there is no screen anywhere). Reassembled and ran engine. Idle is okay again, but as soon and throttle is applied the engine cuts out and dies. Tried to richen and lean the high side first and could not get it to run past 1/4 throttle. Gas is good up to carb with no bubbles. The carb is sucking gas like a hoover. Help?.... TY

I don't kow if you noticed in the article but you do not run regular model airplane fuel in these.

Notice the reduced amount of oil and the very low percentage of nitro?

Crap i was using 10% nitro blend....damn.....where do i buy fuel for this thing then?

Got fuel now from raceshop. The engin still runs like a top when it idless. As soon as you give it throttle above a normal idle it dies. I have tried the needle settings. I have "cleaned" the carb and tried to make sure all passages are open. What am I missing?????

I did get it to rev up to full throttle twice by "pumping the throttle" but normally it just dies.

Maybe try choking the carb slightly on transition to see if the engine is leaning out or not. If it is worse when choking it, it may be too rich, and you might need to lean the low side? Ross

I was wondering if it still had the original DelLorto 5H Carb?

The specific heat of methanol is considerably less than gasoline and if someone stuck a gasoline carburetor on the engine, you will have a serious problem getting enough methanol through the engine to run correctly? In other words, it takes a lot more methanol to make the engine run correctly than it would gasoline. If it has a gasoline carb, it is unlikely you will be able to open the needle enough for the engine to get enough methanol to run correctly?

If it does have the correct carburetor, there are things you can look at on the carb. . . .
[ul][*]Is the carburetor getting the pressure pulse from the engine crankcase?[*]Is the carburetor fuel inlet screen plugged with lint fuzz from a commercial fuel filter?[*]Is the fuel pump diaphragm still have it's integrity? Is it soft and pliable and free of holes and tares?[*]Is the regulator diaphragm still have it's integrity? Is it soft and pliable and free of holes and tares? [*]Check the regulator action of the walking beam lever and needle and seat?
[/ul]

It is still the original 5h dellorto carb. I disassembled it twice now and made sure it was clean and that the rubber was in good shape. All appears to be okay. I cannot get the smart butts at Walbro to help me find a carb. They are less than not interested in my problem. Does anyone know the model carb that would work on this engine.

When you install the carb gasket on the engine, there is a small hole in it that must align with the crankcase pressure hole on the mounting surface, and those must line up with the pressure inlet hole on the base of the carb.

You might also try using the pressure tap on the exhaust header to pressurize the fuel tank (in case you're not already doing so). What type of muffer are you using?

Regards, Dave

Dave has some good advice for you

The problem with us is that we don't know what carb for glow. For gas it would be the Walbro 167-1.

Something else I just happened to think of............................

My OPS 60 Twin Maxi has a Tillotson carburetor installed on it. You might try contacting them (http://www.tillotson.ie/till3.html) and see if they can help. Their HU or HE series of diaphram carbs are in the correct range for your engine size (mine happens to be an HS series, but it's a larger carb). They show a US distributor in Walbridge, OH (Phone 419-838-5911 and 800-537-6212, e-mail address: [email protected]), but I've never contacted them myself........................

Hope this helps,
Dave

V.E Peterson is a large distributor of small engine parts

i have one of these and it can be picky. you need to run (0 nitro.) that meens no nitro, it will not run on any at all. ok now you need to turn the high speed out tell it transitions. that my be alot of turns. my maxiy almost seemed like the needal was going to fall out. the engine also likes a 18X10 wood prop. O and dont get to exsited about the power, it was made to fly big and slow. mine is in a 11 foot airplane that looks like a cub. it dose the job. c-crunch

Thanks for all the info.....still hoping to get this thing working. I am running a 18x10 wood prop. I am also running NO nitro. It is plumbed for exhaust pressure and I put in a new tank and hoses cause I found a small hole in the line going to the carb. The engine still only idles (like a dream too) and will not rev up. I got it to run up twice the other day again but then it started loosing power and died. When I restarted it it was back to the old idle and nothing above a 1/4 throttle. What the "H" is going on I will try to locate a carb from your other suggested resources in hope of getting my auction bird running! Again, thank you all for the help in this trying issue......I need a good carb man I think....anyone work on them??????