HPIBajaForumHPIBajaForum  

Go Back   HPIBajaForum > HPI Baja Garage > HPI Baja Engine and Exhaust


Sponsors
RC Discount Search

Use HBF as the coupon code for 5% off!!!
FullForceRC
TFE
DGI Racing
Killer-RC
HPI Racing
Large Scale RC
LSRC
Team Phatdad RC
Turtle Racing
ONeill Brothers
Axis R/C

Engine Problems

Discussion in HPI Baja Engine and Exhaust forum, started by bigmike35.

OBR
Reply
 
Thread Tools
  #1  
Old 02-02-2017
bigmike35 bigmike35 is offline
Baja Freak
Baja Maniac
 
Join Date: Mar 2012
Location: Richmond, Tx
Posts: 311
Trader Feedback: (0)
bigmike35 is on a distinguished road
Baja 5b Engine Problems

Having weird idling issues. It starts out fine then goes to high rev, back to low/normal back to high as it just sits and idles. It was after it ran for about 10-15mins. I have tried to adjust idle screw didn't seem to have to much affect. Sometimes at the high rev it makes the tires move as well. Not to much but enough when lifted they rotate. Is this caused by a leaked with carb, engine, exhaust or piston ring? Stock carb settings on a wt990 gp290rc motor.

Reply With Quote
  #2  
Old 02-02-2017
Unregistered
Guest
 
Posts: n/a
Trader Feedback: ()
Maybe Just Maybe

New spark plug if ya haven't tried, may or may not do it but a new one seems to fix lots of issues people have lol
Reply With Quote
  #3  
Old 02-02-2017
willie joyner willie joyner is offline
Baja Freak
Baja Maniac
 
Join Date: Jan 2013
Location: Washington, D.C.
Posts: 391
Trader Feedback: (3)
willie joyner is on a distinguished road
Sound like a air leak somewhere to me.
Reply With Quote
  #4  
Old 02-03-2017
Bergheim's Avatar
Bergheim Bergheim is offline
Contributor - All
Baja Maniac
 
Join Date: Aug 2011
Location: Norway
Posts: 255
Trader Feedback: (0)
Bergheim is on a distinguished road
Sounds like the symptoms I had, turned out to be an air leak. Check the carb/manifold and manifold/intake gaskets. If those are ok, check the cylinder gasket then crankcase gasket. In my case it was a blown crankcase gasket.
Reply With Quote
  #5  
Old 02-03-2017
Baja_Crazy Baja_Crazy is offline
Gasser
Baja Maniac
 
Join Date: Apr 2016
Location: UK surrey
Posts: 220
Trader Feedback: (0)
Baja_Crazy is on a distinguished road
sounds like you have an air leak.

spray carb/break cleaner around all intake gaskets, carb, manifold and head gasket
it will most likely kill the engine when you find the spot where its sucking in air.

just be careful with carb cleaner regarding your case seals and if you have a modded carb with a bearing as it will naf up the the rubber.
Reply With Quote
  #6  
Old 02-03-2017
bigmike35 bigmike35 is offline
Baja Freak
Baja Maniac
 
Join Date: Mar 2012
Location: Richmond, Tx
Posts: 311
Trader Feedback: (0)
bigmike35 is on a distinguished road
Quote:
Originally Posted by Bergheim View Post
Sounds like the symptoms I had, turned out to be an air leak. Check the carb/manifold and manifold/intake gaskets. If those are ok, check the cylinder gasket then crankcase gasket. In my case it was a blown crankcase gasket.
Quote:
Originally Posted by Baja_Crazy View Post
sounds like you have an air leak.

spray carb/break cleaner around all intake gaskets, carb, manifold and head gasket
it will most likely kill the engine when you find the spot where its sucking in air.

just be careful with carb cleaner regarding your case seals and if you have a modded carb with a bearing as it will naf up the the rubber.
Ya I figured more on the carb side, replaced the exhaust stuff, haven't cleaned out/rebuild carb since day one (2012). Bought a new carb and rebuild kit, fuel line kit (full force) to replace current one while i try to clean it out and re-use or throw away, new exhaust manifold, gaskets, new top end kit Zenoah 4-Bolt 36mm 29cc Top End Kit (http://www.davesmotors.com/zenoah-96...mm-28-5cc.html), new gaskets for motor, crank. Haven't really replaced anything but the cyl gasket, carb gaskets (tried to clean out sometimes), exhaust. Going to completely break it down and replace what I can. Anything else I should really look at?

I broke it down before I started playing with it the other day and replaced parts/items as needed, just didn't break down the whole motor/carb itself. Pulled carb off to check gaskets.

I can only start it right now by adding a few drops of gas down spark plug, so I think my carb is clogged somewhere. I ran well for the tank, but the idling issues is bad to me. Thanks for the input guys, I appreciate it. Forgot how much i love this hobby and expensive it is lol. Feel like you need to stock up on parts just encase else you are waiting on DDM, whcih means more grazing and buying lol.
Reply With Quote
  #7  
Old 02-03-2017
TheClasher TheClasher is offline
Newbie
1/5th Scaler
 
Join Date: May 2014
Posts: 49
Trader Feedback: (0)
TheClasher is on a distinguished road
Did ya try a spark plug 1 in a million but worth a try
Compated to breaking everyrhing down
Less rhe one minute
Reply With Quote
  #8  
Old 02-03-2017
bigmike35 bigmike35 is offline
Baja Freak
Baja Maniac
 
Join Date: Mar 2012
Location: Richmond, Tx
Posts: 311
Trader Feedback: (0)
bigmike35 is on a distinguished road
Quote:
Originally Posted by TheClasher View Post
Did ya try a spark plug 1 in a million but worth a try
Compated to breaking everyrhing down
Less rhe one minute
Ya i tried about 5 different ones, 2 didn't spark threw those away, the other 3 sparked. 2 were brand new, after pulling about 10-15 times, took it out and it looked bone dry like no fuel was getting on it
Reply With Quote
  #9  
Old 02-03-2017
bigmike35 bigmike35 is offline
Baja Freak
Baja Maniac
 
Join Date: Mar 2012
Location: Richmond, Tx
Posts: 311
Trader Feedback: (0)
bigmike35 is on a distinguished road
Can confirm its a fuel problem, pulled about 10-12times nothing, put a little gas in spark plug hole, fired up after 1 pull.
Reply With Quote
  #10  
Old 02-03-2017
Bergheim's Avatar
Bergheim Bergheim is offline
Contributor - All
Baja Maniac
 
Join Date: Aug 2011
Location: Norway
Posts: 255
Trader Feedback: (0)
Bergheim is on a distinguished road
Quote:
Originally Posted by bigmike35 View Post
Can confirm its a fuel problem, pulled about 10-12times nothing, put a little gas in spark plug hole, fired up after 1 pull.
Not neccessarily, when you pour gas directly into the engine it runs way rich, at least rich enough to compensate for an air leak. Did it run well after you got it to run?
Reply With Quote
  #11  
Old 02-03-2017
bigmike35 bigmike35 is offline
Baja Freak
Baja Maniac
 
Join Date: Mar 2012
Location: Richmond, Tx
Posts: 311
Trader Feedback: (0)
bigmike35 is on a distinguished road
Quote:
Originally Posted by Bergheim View Post
Not neccessarily, when you pour gas directly into the engine it runs way rich, at least rich enough to compensate for an air leak. Did it run well after you got it to run?
The low end/take off sound a little sluggish, top end seemed to be fine. Bottom sounds like it was going to die when applying throttle (boggy). But would the changing in Revs have an effect on this? The idle revs goes high/low/high kinda all over the place.

I would highly suspect a leak somewhere honestly, the carb is really old and never been rebuilt. Sat in the garage for about 2 years. I got new carb (rebuild kit as well), fuel lines, fuel filter (which i changed to new already, black rubber piece on gas tank, gaskets on the way.
Reply With Quote
  #12  
Old 02-03-2017
mark35 mark35 is offline
Newbie
1/5th Scaler
 
Join Date: Dec 2014
Location: Liverpool. UK
Posts: 31
Trader Feedback: (0)
mark35 is on a distinguished road
It maybe your crank seals mate, they don't last forever..
Reply With Quote
  #13  
Old 02-03-2017
bigmike35 bigmike35 is offline
Baja Freak
Baja Maniac
 
Join Date: Mar 2012
Location: Richmond, Tx
Posts: 311
Trader Feedback: (0)
bigmike35 is on a distinguished road
Quote:
Originally Posted by mark35 View Post
It maybe your crank seals mate, they don't last forever..
I have the RC290 but seems like they are all the same parts (mostly) for the 3 engine type/size.
Is this the part you are talking about?

http://www.davesmotors.com/zenoah-21...-seal-set.html

Im referring to this manual from zen http://www.zenoah.co.jp/ddoc/ZENO/ZE...90RC_(208).pdf
I see the seal crank bearing and seal, i picked out the seal on DDM.

If I'm having the engine off and torn apart might as well replaced all I can
Reply With Quote
  #14  
Old 02-03-2017
Unregistered
Guest
 
Posts: n/a
Trader Feedback: ()
I agree may be your crank seal
Check the play of the crank
Reply With Quote
  #15  
Old 02-04-2017
mark35 mark35 is offline
Newbie
1/5th Scaler
 
Join Date: Dec 2014
Location: Liverpool. UK
Posts: 31
Trader Feedback: (0)
mark35 is on a distinguished road
Quote:
Originally Posted by bigmike35 View Post
I have the RC290 but seems like they are all the same parts (mostly) for the 3 engine type/size.
Is this the part you are talking about?

http://www.davesmotors.com/zenoah-21...-seal-set.html

Im referring to this manual from zen http://www.zenoah.co.jp/ddoc/ZENO/ZE...90RC_(208).pdf
I see the seal crank bearing and seal, i picked out the seal on DDM.

If I'm having the engine off and torn apart might as well replaced all I can
Yes bud..they are the right seals.
Reply With Quote
  #16  
Old 02-10-2017
bigmike35 bigmike35 is offline
Baja Freak
Baja Maniac
 
Join Date: Mar 2012
Location: Richmond, Tx
Posts: 311
Trader Feedback: (0)
bigmike35 is on a distinguished road
Finally got all my parts in and rebuilt the motor yesterday! It was a experience none the less, pretty fun at that. Not to many snags minus the engine bearings, had to make a home made arbor press (the whole heat in the oven trick didn't work). Just started it up, took a few pulls and popped a few times before started. Did the 15min warm up and now waiting to cool down to see if it will move next lol! New top end was a big bore kit from DDM.

Edit 1: Started up with a few pulls (kinda sad), wouldn't really move, stalled out. Switch spark plugs, 1 pull and boom, and throttled better than before switching. Ran for 20mins at half throttle, letting cool to run a little harder. Sound very nice cant wait to open her up!

Anyway to revive spark plugs or once foul toss them?
Reply With Quote
  #17  
Old 02-11-2017
Bergheim's Avatar
Bergheim Bergheim is offline
Contributor - All
Baja Maniac
 
Join Date: Aug 2011
Location: Norway
Posts: 255
Trader Feedback: (0)
Bergheim is on a distinguished road
I'd say if the plug fouls after one heat cycle you're running too rich even for break in. I usually foul one plug during a break in procedure. I've tried to repair them (clean everything I can reach with a wire brush and brake cleaner) but mostly they last only one tank afterwards.
Reply With Quote
  #18  
Old 02-12-2017
crankestein crankestein is offline
Newbie
Gasser
 
Join Date: Aug 2016
Posts: 55
Trader Feedback: (0)
crankestein is on a distinguished road
There is a YT video on how to revive them, you need a torch and wire brush. Just do a search, there are a few and does work, they guy shows the complete process.
Reply With Quote
  #19  
Old 02-13-2017
Bahabob Bahabob is offline
Working On It
Baja Maniac
 
Join Date: Jun 2013
Posts: 179
Trader Feedback: (0)
Bahabob is on a distinguished road
Spray the plug with carb cleaner and let dry. Do this a couple times.Oil is the issue not color. Put in it the engine and if it starts just run it.If it doesn't start toss the plug, they are cheap.
Reply With Quote
  #20  
Old 02-13-2017
roadrashracing roadrashracing is offline
Contributor - Baja
Gasser
 
Join Date: Apr 2014
Location: Green Bay WI
Posts: 71
Trader Feedback: (0)
roadrashracing is on a distinguished road
Sounds like to much work for a $2.50 part.
Reply With Quote
Reply

Share This Post


Thread Tools

Posting Rules
You may post new threads
You may 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

Forum Jump

Forum Jump

All times are GMT -4. The time now is 06:36 PM.


Powered by vBulletin - Copyright 2000 - 2017, Jelsoft Enterprises Ltd.
Neither this website nor the forum provided is affiliated with, or endorsed, by Hobby Products International, Inc. (HPI). Further, this website is not affiliated with, or endorsed by, the owners of any the trademarks, service marks or trade names referred to by this website or within the forum unless specifically and expressly indicated. Any trademarks, service marks or trade names referred to on this website or in the forum remain the full property of their respective owners. The opinions expressed in the forum reflects solely the opinion(s) of the participants, visitors and members and may not reflect the opinion(s) of the website owner.