Magnum Problem -- URGENT By ellpee (Read 2,821 times)

[ellpee]

Paying the price for not having done a 100% PDI myself when the dealer didn't request one from Ice Bear.

((ADDED AT 8 PM: WILL POST SOME PICTURES AS SOON AS I CAN FIND THAT OTHER THREAD THAT EXPLAINS HOW. NONE OF THEM SHOWS ANYTHING OBVIOUSLY WRONG, BUT IT MAY HELP THE DISCUSSION IF WE CAN REFER TO THE PIX.))

Left on a run, very bumpy downhill stretch before pavement, halfway down engine started running very rough, wouldn't accelerate. Stopped at roadside, ran rough for a couple minutes. Shut it down, waited a minute, tried a restart, no electrical at first, but got dash lights after a couple tries with the ignition, cranked it, did crank, reluctant to start but did after a bit, still very rough running. Shut it down, pulled it to a safer roadside spot, looked underneath and checked what connections I could see but that was pretty much only the spark plug. Tried one last time, got lights, cranked slowly, tried feebly to fire but no start.

I'm guessing all the bumps shook loose one or more connections, so I'm gonna start pulling plastic and looking, but could use some tips on the most likely problem. Since the dash lights up and with effort it does crank and run, I'm leaning away from electrical and toward vacuum hoses/fuel system. ANY tips at all welcome; will be down there looking but will check back here hourly or so hoping the right guru(s) will check in here and have advice for me.

Needless to say, this has inspired me to garage it and do a full, all-plastic-off PDI before I even think about it going on the road again. That 1/4 mile rough stretch is going to be a fact of life on every run. When I'm done with that, ain't gonna be no connections coming loose ever again unless I want them to.

Oh, since it's a Magnum it probably goes without saying, but it's a horizontal 276cc engine; can't see much of anything on it without pulling plastic, unfortunately.

UPDATE, ~4 hours later: trailered it home, now in garage. Cut an additional access panel through the under-seat plastic so I have a pretty good view of everything carburetor-related.

(1) Don't think it's electrical. Dash lights up, cranks more or less normally, battery reads 12.5v more or less. But on recent start attempts, don't even get a couple "bumps" where it seems to be trying to start. (Did get a couple on earlier attempts, maybe leftover fuel in lines?)

(2) No dangling hoses anywhere I can see, which includes pretty much everything from the fuel pump aft. One stubby little hose goes nowhere and has no clamp, but I've read elsewhere that's just a vent for, I believe, carb bowl overflow.

(3) PS: really impressed with those Chinese hose clamps; I could make something better out of old clothes hangers.

(4) So, my simple-minded analysis is that it's a fuel system issue; either fuel ain't getting to the carb, or what's supposed to happen to it inside the carb, isn't.

So where do I start now? I see:
-- a large (3/8"?) hose coming from the front of the scoot, presumably the fuel tank, to the fuel pump.
-- another large hose coming from the fuel pump to what I would call the "back" of the carb, near the air intake.
-- two smaller hoses (1/4"?) coming from the front area of the carb to a Y connector, and from that back in a slightly larger hose to the fuel pump. I'm GUESSING that's the equivalent of the intake manifold, and that supplies vacuum to drive the fuel pump, but that's purely a guess. Also have no idea why there are TWO small hoses coming off that area of the carb system.
-- two other situations in the middle of the carb structure where a smallish hose comes out of one connection, then goes back into another. Don't have the foggiest idea what those are about.
-- Maybe unrelated, but when the trike is just standing there, not running, there's a fair bit of slack in the throttle cable at the carb end; takes a 60-degree turn of the throttle to take up the slack and start adding gas. Is that normal?

Now comes the part where I throw myself on your mercy. No matter what, I'm going to replace ALL those hoses and use real, gen-yoo-wine USA clamps on them, but where do I begin to figure out why the scoot won't fire up, and runs very roughly if and when it does?

[ellpee]

Oops, in the first picture obviously that should be Hose #1/Hose #2, not #1/#1.

[ellpee]

Wow, I did it -- figured out how to post pix. So if anybody has advice on how to proceed with finding my problem, refer to the pictures if it makes it easier.

[marcystoy]

ellpee - having the same issue with the wife's 2012 Tornado - started fine and sat a few seconds and died. It wont start now either, turns over and acts like it wants to but does not seem like its getting gas.

I even went out and got a new spark plug and gave that a try also, but it did not work.

Going to look at the hoses and all today to see if anything is loose or disconnected.

Update - checked all hoses and connectors out - everything plugged in. Took SP out and verified that I had spark (which I did). Disconnected the fuel hose at the filter and turned Trike over - hardly had any suction on the end of hose. I am thinking that the fuel pump maybe the issue.


Don

[ellpee]

Well, I too am thinking fuel system. Can't find a filter anywhere in my tank to pump to carb. Have read in other threads about wee bits of rubber from cheap Chinese hoses clogging things somewhere along the way. If I don't get any more detailed and focused guidance here in the next day or two, I'm first going to disconnect what I think is the main fuel hose at the carb, and crank the scoot, to see how much if any fuel is making it that far. If there seems to be ample fuel flow at that point I'm thinking I'm going to have to take off the carb and see if crud has clogged the jet(s) or anything else inside the carb. If I DON'T have reasonable fuel flow to the carb, I'll start checking backward all the way to the tank -- a pain, but okay as I now want to replace all the hoses and clamps anyway.

Does yours have those same rinkydink Chinese clamps that look like something made out of a paper clip?

Oh, just re-read your post, and you say you disconnected the fuel hose at the pump and had very little suction. I'm groping in the dark here, but I should think the fuel hose at the pump is output, therefore there should be no suction, but rather some degree of pressure, i.e., squirting fuel when you crank the scoot. If yours is like mine, the suction should be coming from the hose or hoses that come BACK from the carb to the fuel pump, since suction (vacuum) is created in the equivalent of the intake manifold, which comes AFTER the carburetor and BEFORE the cylinder. Geez, I hope one of the gurus shows up here soon to set my thinking straight on all this.

[gatekeeper]

To test for fuel flow, take the fuel line off the carburetor and let it hang in a container. Hit the starter button and let the engine crank over. While the engine is cranking look to see if fuel is spurting out of the hose. It shouldn't just dribble out, should be good steady squirts.

[bhinch]

Welcome...I know you have probably heard this a thousand times...but the engine is just an air pump. So if you do not have the valves adjusted properly, you will not draw fuel to the engine. No compression or low compression will hinder the fuel pumps ability to transfer fuel. The 257cc engine requires the intake valve set to .004 intake and .006 exhaust, not sure about the 244cc. All Chinese scooters do not have the valves adjusted correctly from the mother land. This should be done on the PDI, regardless of year or miles. Life is Good...

[marcystoy]

Ok just came back in from trying gatekeeper post. I get no gas flow at all, so I am thinking the petcock (fuel pump) is not working correctly.

ellpee - yea mine has the paper clip type clamps. From what I have been seeing and reading the hoses at the y connector are vacuam hoses. On your pic showing the petcock - the tube going to the Y are vacuum tubes - the one to the fuel tank is where i found my filter at and that is the line with little to no suction.

your pic are the same set up as mine as far as I can tell.

Bhinch - my wife's scooter has been running fine and then on Sat hers started with no issues idled for a few and then died , has not started since.

[ellpee]

bhinch, me too -- had put almost 200 miles on the trike before this episode and it ran fine except maybe idle a little low. Since I'm getting antsy sitting around doing nothing except reading posts here, I'll probably follow gatekeeper/marcystoy and pull the fuel line off the carb, then crank the scoot to see if any gas is getting from the tank to the carb. As I said in my first post, when the problem arose it did run, very roughly, for a couple minutes; I'm speculating that was leftover gas in the carb bowl, but we'll see.

UPDATE: Pulled fuel hose at carb, cranked scoot, plenty of fuel flow, so that eliminates two potential problem sources. First, fuel path tank to pump to carb is okay. Second, vacuum from carb that DRIVES fuel pump is okay. Also checked spark, all good at the spark plug, jumps 3/4". So, unfortunately it's looking more and more like something inside the carb, which intimidates me. Hoping one of the forum carb experts will chime in soon. Otherwise, have no idea where to start. Would be nice if it's something that can be addressed without completely removing the carb.

[marcystoy]

So strange - two like problems but yet so far different. I am going to call the dealer I brought it from tomorrow. Since these should have a 1 year manufacturer warranty.

[ellpee]

Well, in my case I now suspect unknown crud clogging something important in the carb, but we'll see. Won't take the plunge until I've given folks a little longer to chime in with advice. I rebuilt a carburetor once many years ago, but not a scoot carb; don't want to get too eager and screw something up worse than it already is. In the meantime, though, I can certainly replace all the hoses and clamps with good ol' USA equivalents.

[rapidjim]

I have a a stupid question. Are you sure the spark plug lead is tight on the plug?


Jim

[ellpee]

Not stupid at all. That's actually the first thing I checked at roadside, as it was about the only thing I could see at the time, and it was good'n'tight. Then checked it again in the garage yesterday, first pulled it off and checked for spark (all OK) and then put it back on firmly -- felt it click into place -- and gave it a couple cranks, no go.

Will be buying hoses in various sizes today along with better clamps, and in the next day or two will attack the dreaded carb unless someone here suggests something other possibility. Jim, can I inspect any possible trouble points on the carb without having to remove it completely? Se my pic #2 above -- those two little round thingies look like they could be removed to let me peer inside, but I have no idea what I would be peering at!

[ellpee]

Hey Jim, a side thought. I remember you posting that you give Ice Bear feedback all the time. As I mentioned here, I cut a much larger access panel in the under-seat plastic that makes it much easier to see and, if necessary, work on all the stuff on top of the engine. It came with a small (~6"x6") access panel, but from that one you can't even see most of the good stuff! Same story with my Roketa, it has TWO access panels but both very small and hard to work through. You might suggest to IB to suggest to China that on ALL scoots, not just the Magnum, they consider putting in the biggest possible removable access panel under the seat to make life easier for us customers.

[ellpee]

MORE: went out and bought some US tubing/clamps/connectors and started replacing things. replaced vacuum lines and tried to crank it. Got 4-5 good cranks but no start, then all of a sudden no juice -- dashboard went dead. Swapped out the OEM fuse near the battery (which looked fine) and dash came back to life, so obviously the fuse was NOT fine. Be that as it may, then tried additional cranks, no start. Still plenty of gas getting to the back end of the carb. Even though fuel flow prior to carb was not a problem, moved on to replacing the fuel line from pump to carb; am in the middle of that right now, more news at 11, but no reason that should be causing my difficulties.

BTW, could not find any really small hose clamps appropriate for those little ~3/8" tubes. Smallest size at AutoZone (and elsewhere) works, but takes some fiddling and has to be cranked down REALLY tight. May have to stick with the China solution until I can find a US equivalent.