Joannes High EGT's

[akflyer 1427]

Below is a cut n paste of what I put on the yahoo groups, but here I can post the pics (nice thing about the forum based systems....

Joanne,

On the plug test, we will warm it up with old plugs, shut down, change to new plugs, start and go wide open for 20-30 seconds and kill it with no idle down.

This will show the top end only burn which is what you are interested in right now.

I think you have a B box correct? I just pulled one apart 2 minutes ago just to double check myself (and I am a sucker for ladies in distress) and that front

seal is bathed in gear oil correct? The seal is right behind the pinion gear, and it is lubed with gear oil, therefore, the front seal would be in gear oil if

I am not way out in left field chasing alligators ( i'm not cause I just checked it). If the front seal was leaking, you would be sucking gear oil into it. To

get air around that front seal, it has to pull through the gear box, and the oil that is bathing the gear... damn near impossible.

Has gear oil level gone down? Can you pull the vent on top of the gear box and put a slight amount of air pressure to it and see if it holds? I am not

sure that vegas would be giving odds on sucking enough air through the front seal and gear oil to give you a high reading, unless it was a catastrophic

failure, in which case you would be burning gear oil and would darn sure know that smell and the cute little blue cloud of mosquito killer coming out the

exhaust.

Lets think about the WD 40 trick lock wood had you do. Remember when your gear box was leaking due to the pinched oring? That is what seals off the gear box

and front seal chamber from the block.

Do you know how to get WD 40 from the little hole in the side of the gear box that you shot it into, to the front seal to see if it is leaking... It is the

same way you put an elephant into a shopping cart. You take the S out of safe and the F out of way.... your right there is no F in way, unless the rubber

oring was leaking also and you would know that by gear oil running down the engine again and blowing out the two tell tale holes in the side..

When the case was split were the two mating surfaces cleaned, then was a sealant applied to them correctly before re-assembly?

I am leaning more towards the carb boot leaking, a cracked primer line (if you use a primer) or a leak between the crank halves, or oring on the crank on the

bearings (which you cant change without splitting the crank)or something plugging off the main jet and high speed circuit. Fire it up, then squirt WD 40

all around the mating surfaces between the two case halves and see if it picks up any RPM or it may even choke it down if the leak is bad enough.

You can pull the gear box in about 5 minutes after you drain the oil and get direct access to the front seal.

I will post up pics on my avidfoxflyers site in a just a few to point out what I am saying about the front seal and trouble I am having thinking that it could

actually be the culprit.

Leni

Front seal and the oring that seals off the chamber you shot WD 40 into..

Another shot of the same

the groove that the oring seats into showing the elephant into the shopping cart thing....

One more shot just for good measure.

[C5Engineer 1170]

I've been following that issue over there. They could have torn the engine back down several times in all the time they have spent coming up with theories. If they keep running it with an air leak the problem will be easy to find when it seizes.

[akflyer 1427]

I've been following that issue over there. They could have torn the engine back down several times in all the time they have spent coming up with theories. If they keep running it with an air leak the problem will be easy to find when it seizes.

So what to you think Joey, am I outa my mind on this one I was sitting in the garage this AM and thinking about this and a little light bulb went off in my head... A few quick turns of the wrench walla.. kills the main theory over there in my mind

[C5Engineer 1170]

So what to you think Joey, am I outa my mind on this one I was sitting in the garage this AM and thinking about this and a little light bulb went off in my head... A few quick turns of the wrench walla.. kills the main theory over there in my mind

I think your right on the money. Air is the only thing I've seen to cause one cylinder to run hot.

[n757jh 1]

I've been following that issue over there. They could have torn the engine back down several times in all the time they have spent coming up with theories. If they keep running it with an air leak the problem will be easy to find when it seizes.

Go easy, Joey. I'm on a steep learning curve here. We started ruling out the easy things first. I got on the phone with Jack at LEAF, he suggested the WD-40 into the B gearbox hole, which didn't seem to have much effect even when squirted directly into the carb.

You have no idea how much more difficult it is for us to work on this, than it is for you. Hell, I don't even shake hands with people anymore before warning them that I have arthritis. And Dan's had some sort of cold/flu for four weeks now. The airport is 40 miles away. My hangar is unheated and drafty with a dirt/gravel floor, and it's only getting into the low 40's here now.

We're doing the best we can. So if you have something constructive to contribute, I'd appreciate the help.

[C5Engineer 1170]

Sorry Joanne... I saw that you had already ruled out all the easy stuff. It just seems to me that your wasting your time at this point playing on all these crazy theories. Yard the engine off the plane and take it home where it's warm and tear into it. Beings it was just tore down I suspect something did not go back together just exactly right. I just spent over 20 hours swapping a new blue head into my plane. I took it home so that I could be in the comfort of my garage and family. I guess my contribution would be if it were me I'd tear the thing apart and put new seals in it before you melt down the hot cylinder. It's been mentioned but the CPS catalog as well as the 582 rebuild DVD has good procedures for doing a leak down/seal check. Wouldn't ether work far better than WD-40 for looking for a leak? That's what I always use when looking for vacuum leaks on a vehicle.

PM me your address if you want my 582 rebuild DVD... very good info on it.. I got it free and would gladly pass it along. I have a zero time blue head that I hopefully (fingers crossed) won't have to tear into for a while.

If your not comfortable working on it check out Rotax Rick of Red Gold Rotax on barnstormers. He'll rebuild it better than new for cheaper than anybody else I've seen using genuine Rotax parts.

Good luck with your issue...hopefully you get into the air soon.

[akflyer 1427]

Go easy, Joey. I'm on a steep learning curve here. We started ruling out the easy things first. I got on the phone with Jack at LEAF, he suggested the WD-40 into the B gearbox hole, which didn't seem to have much effect even when squirted directly into the carb.

You have no idea how much more difficult it is for us to work on this, than it is for you. Hell, I don't even shake hands with people anymore before warning them that I have arthritis. And Dan's had some sort of cold/flu for four weeks now. The airport is 40 miles away. My hangar is unheated and drafty with a dirt/gravel floor, and it's only getting into the low 40's here now.

We're doing the best we can. So if you have something constructive to contribute, I'd appreciate the help.

I would be tempted to send a large burly Italian guy to kick Jack in the ding ding for giving out some bogus advice for free It's all good, and we will see what we can think of with the aide of a toddy or two to help you out!

[akflyer 1427]

I know you are very new to working on 2 strokes, and we will see what we can come up with to help get you back in the air. Nothing is more frustrating than working on an engine to only have problems...

You never said if sealant (proper crank case engine sealant) was used between the case halves. The only thing that will make a 2 stroke run hot like that is a lean fuel mixture, be it too little fuel, or too much air due to a leak and timing.

I am sure you have already run through all of this, but just double checking (because I hate the jumbled up mess of the posts on the yahoo groups site that makes it hard to sift through the info).

Check Carb boots for cracks. Rotax Carb boots suck. JBM Industries makes a much better boot with a better rubber compound that lasts much longer. Click here for JBM Industries

Primer lines OK, or if not used the caps are in good shape and sealed well.

Rotary valve timing is correct. The third I did I was looking at the book (engine right side up) and working on an engine that is upside down... I timed it to the wrong cylinder. Didn't run too good!

Carb bodies cleaned out. Pull the main jet and make sure there is no blockage, even the tiniest hair.

Plastic screen that goes over the main jet was not damaged when the float bowl was put back on.

Float level set properly.

Did you mess with the in flight mixture on the cylinder that was running hot. Crank that open a turn or two. My plane normally runs one cylinder a turn richer than the other to keep the EGT's the same.

Bad plug wires should make it pop snort and fart or not run at all, but I can't see it making the cylinder run hot.......

Hey, just thought of this.... You changed the stator correct.. did you change the trigger coils are they the slotted type that you can change timing on, or the fixed round hole that you can only adjust gap??? If one of them is off, I can see it hosing up the EGT's, and you will really see it at high RPM as it does advance a small amount with the Ducatti ignition.

Let me know what you have done so I can rule out issues in my mind and see if we cant get this bugger back in the air for you!

[Trackwelder 12]

WD 40 used to work for that sort of thing, it was even a great starter fluid for diesels . But some years back they switched the propellant from propane to something inert. When trouble shooting anything I always start with the last thing changedbefore the problem started. I have yet to become familiar with the Bing carburetor but on the standard mikunisused on snowmobiles it is not unheard of to have a clip come off the needle makes short work of your cylinder. Good Luck

[n757jh 1]

WD 40 used to work for that sort of thing... some years back they switched the propellant from propane to something inert.

Well, that explains why squirting it directly down the throat of the carb didn't have much effect. Thanks, didn't know that.

Bing carburetor... it is not unheard of to have a clip come off the needle makes short work of your cylinder.

Arctic Sparrow mixture control = no clips.

When trouble shooting anything I always start with the last thing changedbefore the problem started.

Good advice. This is all happening within the first three hours after a rebuild. There's a lot that gets done to remove/reinstall... and then there's the other problems we were chasing down prior to this one... the mind boggles.

Joanne

[n757jh 1]

582 rebuild DVD...

Thanks very much for the offer, Joey - I do have one, it is very good.

Joanne

[n757jh 1]

The List:

You never said if sealant (proper crank case engine sealant) was used between the case halves. The only thing that will make a 2 stroke run hot like that is a lean fuel mixture, be it too little fuel, or too much air due to a leak and timing. No way for me to know, the rebuild shop put it back together.

Check Carb boots for cracks. Rotax Carb boots suck. JBM Industries makes a much better boot with a better rubber compound that lasts much longer. Click here for JBM Industries Existing already were the newer, thicker type; had spares on hand so replaced them with new just to rule them out. Not sure if they were JBM, they are thick as well and just slightly different than the old ones, so might be.

Primer lines OK, or if not used the caps are in good shape and sealed well. Had some red line on hand, so replaced to rule them out. Don't like the red, can't see through it, going to replace again with blue.

Vent lines also replaced, four holes properly drilled in each.

Fuel lines from pump to carbs replaced, new brass filters.

Rotary valve timing is correct. The third I did I was looking at the book (engine right side up) and working on an engine that is upside down... I timed it to the wrong cylinder. Didn't run too good! The rebuild shop would have done this... the engine did run ok during the static runup to check prop pitch (6250 rpm) so I think this is ruled out.

Carb bodies cleaned out. Pull the main jet and make sure there is no blockage, even the tiniest hair. Swapping the carb bodies should have ruled this out. No harm in cleaning them out again.

Plastic screen that goes over the main jet was not damaged when the float bowl was put back on. Screens are good - always handle them carefully.

Float level set properly. Yup.

Did you mess with the in flight mixture on the cylinder that was running hot. Crank that open a turn or two. My plane normally runs one cylinder a turn richer than the other to keep the EGT's the same. Yes, but it didn't come anywhere near overcoming the 200 degree difference - that might be more than even a main jet change could overcome. Yes, I've adjusted one a turn richer than the other in flight as well.

I did mess with the idle air mixture and idle rpm, got it set and ran it for a little bit. Next time the engine was started it didn't run quite as smoothly, and this temperature difference showed up in flight. I think that's just a coincidence. Especially since swapping the carb bodies didn't move the problem. Those adjustments should only have an effect on idle.

Bad plug wires should make it pop snort and fart or not run at all, but I can't see it making the cylinder run hot....... We were just thinking, since the wires are 20 yrs old, and two of them are jammed behind the exhaust bracket (coils mounted on inside of firewall, lower center between pedals), it's a good time to reroute those and replace them all, and new caps too. Rules those out as causes.

Hey, just thought of this.... You changed the stator correct.. did you change the trigger coils are they the slotted type that you can change timing on, or the fixed round hole that you can only adjust gap??? If one of them is off, I can see it hosing up the EGT's, and you will really see it at high RPM as it does advance a small amount with the Ducatti ignition. Actually we found a crossed wire, did the ohms checks after fixing this and it checked ok, so we left the old one in. Old triggers with round hole. Gap checked ok.

The rotary valve oil level was down about a teaspoon. It never used oil like that before the rebuild. I filled it back up but haven't run it again.

We are in the midst of setting up a vacuum/pressure test.

Need to redo the compression test as it was done before this problem started.

[n757jh 1]

Leni,

The new spark plug wires are done. Question: what's a good way to keep the coil end of the connection secure? This new wire is stiffer than the old, and slightly smaller in diameter. Just pushing it onto the pin and covering it with the boot doesn't seem like enough. The braided shield over the wire is grounded to the coil mounting bolt, which helps hold it, but not securely. What do you think? Safety wire?

Joanne

[akflyer 1427]

Leni,

The new spark plug wires are done. Question: what's a good way to keep the coil end of the connection secure? This new wire is stiffer than the old, and slightly smaller in diameter. Just pushing it onto the pin and covering it with the boot doesn't seem like enough. The braided shield over the wire is grounded to the coil mounting bolt, which helps hold it, but not securely. What do you think? Safety wire?

Joanne

I will go take a look at one tomorrow. I know the caps screw on, and every other coil I have seen screwed the wire into it and that is all that holds it on.

[akflyer 1427]

I will go take a look at one tomorrow. I know the caps screw on, and every other coil I have seen screwed the wire into it and that is all that holds it on.

The wires do thread onto the terminals in the coils and the caps. A dab of dielectric grease then screw them on to the coil and cap. Make sure the rubber boots seal up around the wires.

[akflyer 1427]

Did you check the connections on the EGT probes? You should have a set of wires coming off the back of the gauge, then the thermocouples plug into that wire. Make sure those connections are good. I had one set drive me nuts, and even though the plugs looked good, I was getting high and erratic EGT readings... turned out the extension wire was hosed up. I learned this after changing probes and gauges twice.