Dub Jett Engines Support Bob Brassel of Dub Jett Engines provides direct support here for Jett Engines.

BSE 120L

Reply

Old 11-15-2009, 03:28 PM
  #1  
Broken Wings
Thread Starter
My Feedback: (20)
 
Broken Wings's Avatar
 
Join Date: Jan 2003
Location: Cocoa, FL
Posts: 2,085
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default BSE 120L

Bob, I've got a BSE 120L and I'm having trouble getting the engine to transition well. I've got it on a large Profile model in the horz. position. Using Sig Champion 15% syn/castor, a Top Flite Power Point 16x6 wood propeller. The needle is mounted off the engine on the fuselage. McCoy 59 plug. Long Red Jett muffler.

The engines runs great, idles well, full throttle is fine, but it "puffs" smoke when running in the midrange. At 3/4 or better throttle I get a good smoke trail. When I throttle back it clears up as if its leanning out and will "puff" a wisp of smoke.

I've richened the low speed one turn and it will die on take-off. Went a half turn, one quarter turn, eighth, etc.

On the bench the initial settings work well.

Any suggestions?

Broken Wings is offline  
Reply With Quote
Old 11-15-2009, 08:05 PM
  #2  
bob27s
My Feedback: (19)
 
bob27s's Avatar
 
Join Date: Apr 2002
Location: Cleveland, OH
Posts: 5,576
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: BSE 120L

Thanks for writing.....

First, not wise to change the low speed mixture setting. Dub dials that in at the shop. It is not the same as most other low speed mixtures, it is more of a midrange mixture adjustment. Moving it from the stock position more than 1/4 turn either way can and will cause things not to work right.

The jett-stream (red) muffler is a tuned device. As the engine stages on or off of the pipe, there is a point at which the mixture will seem rich (or lean) as the engine trys to stage on the muffler (pipe effect).

From what you described, it sounds like you may be running slightly rich on the top end. Generally this is ok.

The best way to work with the midrange is to adjust the ignition timing. That is done with the glow plug. The Mc59 is usually pretty good. But it sounds like you might want to try using an OS 4C plug. Yes, the 4cycle plug. It is a very hot plug, and the hooded element allows the engine to get through a wet transition (similar to what old idle bar glow plugs use to do).

Give that a try.

Do not focus on what the exhaust looks like. That is a function of the oil in the fuel, it is not really an indication of how the engine is running.

Find peak ground rpm on the high speed needle, back off from that peak about 500 rpm, and that should be perfect for flight.

Also, be certain the prop you chose runs in the rpm band the engine/muffler prefers. You want to see about 10,500 peak ground rpm or more. Anything between 10K and 12K is a good target with this engine. Might mean backing off to a 15x6 for a few flights, until you get a little time on the engine, and get use to how it runs.

Let me know how you make out.
bob27s is offline  
Reply With Quote
Old 11-15-2009, 08:09 PM
  #3  
Broken Wings
Thread Starter
My Feedback: (20)
 
Broken Wings's Avatar
 
Join Date: Jan 2003
Location: Cocoa, FL
Posts: 2,085
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: BSE 120L

I bought the engine used so I don't know the history. Maybe I should send it back to Dub for re-calibration and a general check-up.
Broken Wings is offline  
Reply With Quote
Old 11-17-2009, 09:06 AM
  #4  
bob27s
My Feedback: (19)
 
bob27s's Avatar
 
Join Date: Apr 2002
Location: Cleveland, OH
Posts: 5,576
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: BSE 120L

A checkup can be helpful.

But you might be better off putting it back on the test bench and starting from there. Instructions on setting the low/mid needle are on the jett website. Typically not difficult to do.

Bob
bob27s is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service