Notices
RC Fuels Nitromethane, Castor Oil, Synthetic, heli fuel, 4 stroke, etc...Fuel Q&A is here!

Fuel will not run engine.?????

Old 12-31-2003, 10:05 PM
  #1  
WALKERS210-RCU
Senior Member
Thread Starter
My Feedback: (36)
 
Join Date: Feb 2002
Location: Sipsey, AL
Posts: 387
Likes: 0
Received 1 Like on 1 Post
Default Fuel will not run engine.?????

I was told by several club members that to get great performance from a 91 4stroke to use 30% Heli fuel. After reading an article about Satio engines and they recommended the same thing. Well I bought a gallon of fuel, I used it first in a ST 90 2 st and performance was outstanding. Put it in my OS 91 4stroke, engine was running great at about half throttle when it stopped ( luckily on ground) and spun the prop off. Replaced prop and tried to restart engine. Only made feeble attempt at firing and running. Tore engine down expecting to find warped valve stem or broken springs. Everything was in top shape. Reassembled and tried it again with same results. I put the plane aside and more or less was ready to write the engine off. I pulled out another plane to get it ready for flight, fueled it with same fuel and it would not run, sputter at best, I removed fuel and put in 10% and engine ran perfect. Pulled out the 91 4stroke and fueled it with 10% engine runs great. Still in the 90 2 stroke the 30% heli fuel runs great ???
What am I missing, after 25 yr in this hobby I have never seen anything like this.
.
Old 12-31-2003, 10:56 PM
  #2  
Warren
My Feedback: (72)
 
Warren's Avatar
 
Join Date: Oct 2002
Location: Alpine, CA
Posts: 473
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fuel will not run engine.?????

Did you readjust your main needle and richen it up?

You will have to go out a good turn and sneak back up on the correct setting, and also readjust your low idle needle.
Old 12-31-2003, 11:13 PM
  #3  
LarryC
Senior Member
 
Join Date: Oct 2002
Location: Brookland, AR
Posts: 406
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fuel will not run engine.?????

What Warren said is correct. Nitromethane requires a different fuel/air ratio than does alcohol.
A four stroke backfiring and losing a prop is a sure sign of a too lean mixture.

By the way, I just bought my first Saito, a 91. Really nice motor; I had other 91s but I wanted the light weight of the Saito.

Larry
Old 01-01-2004, 11:56 PM
  #4  
Sport_Pilot
 
Sport_Pilot's Avatar
 
Join Date: Jan 2002
Location: Acworth, GA
Posts: 16,916
Likes: 0
Received 1 Like on 1 Post
Default RE: Fuel will not run engine.?????

Sounds like 30% is too much nitro for your OS .91. They have a bit higher compression ratio than a Saito. You may try a colder plug. May I suggest a K&B 4C plug? Colder on the top end but will still give a great idle.

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 -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.