Moki 180 Fuel problems
 

I am having a problem with the MOKI 180. It starts when primed, then runs for 1 minute, then stops.Runs out of the Prime.It is not getting fuel, the way I see it. I looked at the line to the carb., no fuel? Main neddle valve out 5 turns per instructions to start.
I pulled the tank, 3rd time, replaced all the fuel tubing outside the tank with 1/8" tubing and have put on clamps on the fittings. I pulled the fuel lines inside the tank, whichis 3?32" normal tubing and replaced. The clunk is fine,no obstructions.Pressuriezed the tank, no leaks. So now, I don't know what is happening.

I pulled the engine, inspected the carb, looks OK, nothing loose and O ring is good. The Low end diskvalve is centered with the grove. I richened, same problem, then leaned, same problem?
This engine is supposed to work with 3/32 "fuel line, which I replaced with 1/8" tubing, no obstructions whatsoever.
The fuel take is almost level with the carb spraybar. What is going on here? That thing should suck fuel like nobodys business. I am using a Slimline Smoke Pitts Muffler, with the Smoke port closed off, Not set up for Smoke yet. I have tried OS #8 Plugs, and K&B plugs, no difference.
The engine is mounted Horizontal (sideways). if that helps.

RE: Moki 180 Fuel problems
 

Hi

Might dis-assemble the carb and give it a good cleaning. Some times you get CRUD in the spray bar. Also when it dies, does it go lean and die, or just die? How old is the fuel? Moki's love low or no nitro. Have you changed the glo-plug? Check back plate and head bolts for tightness. Any scoring on the piston and sleeve?


Vince

RE: Moki 180 Fuel problems
 

Thank you for your reply. This is a brand new engine. I broke it in on a test stand. When doing this, I had a lot of smoke coming out the muffler. I assumed it was very rich. I used Power Master FAI. fuel, which is recommemded, Brand New fuel. The engine seemed lean to me, even though it was smoking out the exhaust.
When I prime the carb, it runs fine, after it looses the prime fuel, it stops. It doe's not go lean or rev up at all. Same thing if I advance the throttle, it just stops. Never ran into this with 2 strokes, but this one is a problem. I was using a Moki remote needle valve, which I bypased, just running in on the carb needle. When using the remote, I opened the carb needle valve 6 turns out, rich, then tried to adjust the remote, then all of this happened, so I just went back to factory settings,bypassing the remote, and it stops after repriming, stalls on high end when advanced.?
I was using an OS/#8, new, then tried a new B&M plug, no difference. Same result.
The back plate it tight, no leaks. I pulled it just to check, very light scorring from the crankshaft, not much. which may be normal , I don know, but to me it should not be touching the backplate at all. I have not pulled the head, no reason too, brand new engine, I still don't understand it..
My concern is, why would the backplate be scored at all, it's 1/8 inch away from the crankshaft. To me there should be no visiable marks on the backplate at all.

RE: Moki 180 Fuel problems
 

Flaphappy
My Moki 210's will not run wirhout the Perry regulating pump. Tower has them for 34.99. I know some people do not need them but I ahave two 210's with pumps and they are very dependable. The 180 and the 210 are nearly the same engine.

RE: Moki 180 Fuel problems
 

Hi FH, in reading your posts the is one thing I did not hear you check for and that is is muffler nipple clear. You said it was a new engine and perhaps the muffler also had some machineing flotsom in it which could plug the muffler nipple so definately run a pin through it completely.

I have no problems at all running my 1.8 without a pump and much the same setup you described. I am gonna check tonight in a bit the needle position where it has been running.

John

RE: Moki 180 Fuel problems
 

I have pulled the backplate, in hopes to drill it with a pressure fitting for a Perry pump. I hav not drilled it yet. Why do they not tell you, you need a pump?

RE: Moki 180 Fuel problems
 

John: yess the nipple on the Muffler is clear. I used a plastic pump to test it and it is clear of any obstruction. I could feel air coming out the 2 exhaust pipes, so it must be clear.? I will run a pin through it tomorrow, but I don't think that is the problem. True, the muffler is not creating any back pressure, or at least not enough to pressurize the tank, that's why it dies, I think. I am thinking of using a Perry pump to see if that makes it work and bypassing the muffler altogether.

RE: Moki 180 Fuel problems
 

If you're running a pitts muffler try plugging one of the pipes, this will give you more pressure. Also I've always ran an OS type F plug & never a problem.;)

RE: Moki 180 Fuel problems
 

The Perry Regulating pump of course will help.

I just checked and the main needle (I use only the carburator mounted needle) and the sweet spot for my engine has been around 1.5 turns open from fully closed.

I have no idea what any manuals have suggested I just opened the needle up perhaps four or five turns initially and arrived at the setting where it is now by pinch tunning. It has been quit stabile at that setting.

Let me describe the priming technique I use, by the way mine is a side mounted 1.8 also. First I open the throttle barrel completely and then completely cover the venturi (not just covering the exhaust outlets that won,t pull the fuel). With the throttle open and venturi covered I will then pull around five to ten blades and I do it untill the fuel is completely running out the venturi and my finger is soaked.

Its at this point that I either use the starter or bounce start the engine by bumping the engine backwards aginst compression with the spinner.

Hope you have better luck.


John

RE: Moki 180 Fuel problems
 

I don't use a pump with my Moki 180.. don't need it. It runs with needle open about 2.5 or so turns out.. and the low end disc lined up notch to notch. It does like to start WET.. I prime it until it spits just a tad of fuel on my thumb... then just a back-flip and its running.

Don't drill a thing... . especially that back-plate... you might just end up plugging it back up..... as these engines don't need pumps unless you're running fuel from the rear of the fuselage.. in any standard aerobat or warbird though... no fuel pump is needed. I use an 18x10 Menz prop, and any kind of FAI fuel I can find.. even made my own a few times.. theres on real savings doing that so I just buy it ready made now..

Theres an obstruction somewhere though... whether its in the fuel delivery, or air system, or fuel tank, or pressure fitting... somewhere somethings not right. I've used an OS 4-stroke plug from day one also, with no issues(that I would install immediately)....... medium fuel tubing also works fine. Theres not any magic $50 pump that's going to fix whats wrong with your engine.. Don't spend money until you know what's wrong... as you could end up spending alot that you might not need too.

These are one of the best engines you'll ever own... but if you get tired of fighting it.. PM me.. I'll take it off your hands. :)

RE: Moki 180 Fuel problems
 

I replaced all the fuel lines in the tank and to the engine. I used medium fuel tubing. I pressurized the tank, it's held pressure,Replaced the muffler with another Slimline Pitts W/ smoke. Blocked off the smoke port. Primed the engine, it ran until it ran out of the prime. This is a brand new engine, and why will it not run? The Low end Idle disk is at thenutral notch, havn't touched it since replacing all the tubing. I ddi try to lean the low end, same problem, the richened the Low speed again, same problem.. I even put clamps on the tubing.. This is very frustrating tosay the least.The disk looks fine ,not loose,So now what?

RE: Moki 180 Fuel problems
 

I am having the same problem with my Moki but it has sit for awhile I am just wondering if I could have a plugged inlet to the carb? Anyone ever have that happen? I have a Perry pump on mine having the same issue? I hate to barge in on your thread, sorry. Maybe we can both get answers. Thanks Mike

RE: Moki 180 Fuel problems
 

You should not need a pump. Many of the Pitts mufflers have way to little restriction for their volume. I would plug up one pipe, or restrict both. It will be quiter and will have little to no loss in performance.

RE: Moki 180 Fuel problems
 

Mike:
You did not do anything wrong, thanks. Today, I put in a brand new tank, with all new tubing, and endeded up with the same problem. In fact, I placed the new tank, above the origional, I did notice when I tipped the plane on the spinner, fuel came gushing out the carb. I pulled the carb, the oring is not split, reinstalled it, same thing. Fuel coming out the carb with the throttle closed?
May I remind you this is a brand new engine.Something is wrong with the carburator, I have fought this for a week now, pulled the engine and I am sending it back to BJ's engine's , to have him look at what is happening. Iam tiredof messing with this engine right nowafter a week of frustration. There is a leak in the carburator somewhere, and I can't trace it down. Bill Jenson told me I don't need a perry pump or a cline, the engines do not require it, as they should. You don't have to plug up one muffler pipe for more pressure , according to Slimline and you don't need any pump or regulator..

RE: Moki 180 Fuel problems
 

I got mine going, I changed some fuel lines, but I think more importantly I got a good solid prime! I ran half a tank with out any issues, going to try and take maiden flight tomorrow. I am so excited, like a kid in a candy store!!! Hope all goes well suppose to be beautiful with very lite winds temps in the upper 70's.


Thanks all

Mike

RE: Moki 180 Fuel problems
 

About the only thing I haven't read(and I could have missed it) is the actual inlet to the carb, as well as the needle/seat ass'ly being disassembled and blown out/inspected. Obviously these lines/paths should be clear of all/any micro debri and such.... and yes.. again, you got good info on this engine not needing anything in the way of a pump/regulator.. nothing other then pressure from the muff.

I would go as far as I could with disassembly(as your skills and tools allow of course).. to possibly take off/out that needle-seat assembly off that carb... have a look at what goes on in there if you can..

Also.. if this engine will start and seemingly run out the prime.. what happens when you open the main needle.. in whatever increments.. basically.. can you get and keep this engine running with the needle way out(further then we all might think anyway)...?

I've ran mine with the OS type-F plug from day one... with an 18x10 prop(Menz)...Bisson pitts-style muff.... Morgan FAI fuel for the most part(It was not finicky about fuel. as long as it didn't have nitro).. med. fuel line, using a 24oz tank, w/3-line set-up. Its one of the best(if not the best) engine I own... I sure am curious whats wrong with your engine... hmm.. (scracthes head...)..

Please post back with any revalations.. thanks. :)

RE: Moki 180 Fuel problems
 

DGrant:
I did pull of the main needle valve seat, removed the needle valve, cleaned both parts with carb cleaner, reassembled, and started the engine, same problemm occurred.
It won't pull fuel to the Carburator. I replaced all the tubings, put clamps on the tubing inside the tank and on all exterior fittings.
I could not remove the Low speed notched disk, it would not come out. I got tired of fighting this issues after a week or so, packed up the engine and sent it off to BJ's Engine Service in CT.
I had another Moki 180, installed it with everything the same. Finally the main needle valve was adjusted to3 turns open, and I adjusted the low speed to 1 click rich, ran great Good transition after the adjustments Tacked the engine at 8500 WOT with a MA 18X8 prop.. I am waiting to see what Bill Jensen finds, I'll bet it's either a bad "O'" ring either in the low speed disk or the hi speed, I checked the hi speed o ring and it looked fine?? Mind you, the origional engine was brand new, the other one I installed was like new, I purchased it on RCU
The guyswho responded to this thread, gave me their opinions, which is great and I thank them, however plugging up one pipe on a Pitts Muff, or installing a Pump or Regulator is not nescessary as you stated, I agree and so did Bill Jensen. These engines run great , once tuned properly,
I used Medium fuel tubing with clamps, 1/8" ID, and these engines will work on 3/32"tubing as well. They do suck fuel, so I opted for the larger size.. That didnot make any difference on the origional problem.

I agreed with you, do not drill anything, and I did not.
If the engines neededa Perry pump or cline reg, they would have stated that, which they do not.You do not need to drill out the clunk to 5/32", it works fine with any clunk. I used the origional one I installed, works fine.

RE: Moki 180 Fuel problems
 

Hi Flap.. OK then.. we'll wait and see. Please post back when you get a chance as to the findings... It sure sounds like you've done everything by the book.. It must be an internal component as you said, that might have either been installed incorrectly from the factory, or faulty from the factory. One of those "anomalies" it seems. haha..


Hopefully we can learn.. sorry it might be at your expense this time.. but I'll pass it forward sometime soon I'm sure. Have a great weekend. :)

RE: Moki 180 Fuel problems
 

If that Moki has a sleeve...it could be rotated in the wrong position. Maybe....Maybe not????

RE: Moki 180 Fuel problems
 

I just stumbled across this thread. I have two 2.10 Mokis. The one in my 80" Midwest Extra 300 hadn't been run in a long while, so I cleaned the carb thoroughly, installed new o-rings (from the Moki parts lady in England) and re-plumbed the tank. It behaved just like yours - wouldn't pull fuel, etc. This plane had been flown with this engine and carb for several years! It wouldn't run on the bench, either. Finally, I swapped the (cleaned/rebuilt) carb from the other 2.10 and it runs just like it used to. Hmmm??? I put the carbs side-by-side and compared absolutely everything, but they appear identical. I will again disassemble the suspect carb to check for possible swarf that I might have missed. Once I find what the issue is, I'll report back. I can test the suspect carb with the #2 engine on the bench.

Let us know what Bill says - he is very knowledgeable.

JIm

RE: Moki 180 Fuel problems
 

CaptJohn:
It is a new engine like I mentioned. You might be onto something though. I noticed the other engine I ran today, had more compression than the one I sent Bill. We'll see what he finds.

RE: Moki 180 Fuel problems
 

SQR flyer:
I will report on this thread what Bill finds. It's funny, I did everything I knew how to do, so it's got to be either a carb issue, possibly ring or sleeve, I don't know yet. I have read other threads, and they are reporting the exact same issue I have. Something is wrong.

RE: Moki 180 Fuel problems
 

I did some more testing - I have a friend's 2.10 here for minor repairs. It runs well, so I did some experiments with his carb and my bad one. Note that a very careful inspection of my carb shows absolutely no dirt, gum, etc. in any passageway.
With his good carb, the HS needle will completely shut off the incoming fuel. With my bad one, it still allows (large amounts) of air to enter, even when closed. His NV and even a BRAND NEW one made no difference. Maybe the spraybar opening is worn to the point that the NV won't seal it off? This could explain fuel gushing out the carb when the plane is on its nose, as noted in a previous post.

This almost makes it seem like the engine is flooded! That would explain the fact that I can’t get it to pop once it quits.

Jim

RE: Moki 180 Fuel problems
 

Looks like your on to something now....and it makes sense to me! Capt,n

RE: Moki 180 Fuel problems
 

Jim:
Thanks for your input. I did a test after I ran the engine, I put a piece of tubing on the carb. and could air through it, then I closed the needle valve, and I could not blow air through it. That tells me the spray bar is ok, or did I miss something? When I tipped the plane on it's nose, the needle valve was where it was set when running, opened about 3 turns. I would expect a small amount of fuel to come out, but it was like there was no needle valvein to begin with, I really couldn't see where the fuel was leaking out, just to much everywhere.
As I mentioned, I did pull the carb and reseated the "O" ring prior to this.
Paul