Go Back  PPRuNe Forums > PPRuNe Social > Jet Blast
Reload this Page >

Pull starter.

Jet Blast Topics that don't fit the other forums. Rules of Engagement apply.

Pull starter.

Old 30th Dec 2020, 12:56
  #1 (permalink)  
Ecce Homo! Loquitur...
Thread Starter
 
Join Date: Jul 2000
Location: Peripatetic
Posts: 11,522
Pull starter.

A question for the mechanically minded.

I have got my hands on an unused 1.5Kw portable generator with a cord pull start which wonít work properly. Which is maybe why it was passed on.

Pull start is integrated into an engine cover which bolts on. Works perfectly when unbolted. Taken it apart and checked and rewound spring and cord and refitted the cam catcher which pops out when pulled to engage with engine and retracts when pushed in.

Bolt it onto the machine and pull the handle and it engages and the motor turns - but the cord fails to retract. Start unbolting it and after loosening a couple of the bolts it zips back in as expected. No areas where the cord seems to catch or other obvious pressure points.

And ideas? Otherwise Iíll sell it. For parts, which seems a waste for a brand new machine.

(Canít find anyone who sells the parts separately - Bruder Mannesmann 12951)
ORAC is online now  
Old 30th Dec 2020, 13:13
  #2 (permalink)  
 
Join Date: Feb 2000
Location: UK
Posts: 1,441
Pose question here https://www.model-engineer.co.uk/
Highly competent membership and helpful responses.
Cornish Jack is offline  
Old 30th Dec 2020, 13:13
  #3 (permalink)  
 
Join Date: Feb 2006
Location: Station 42
Age: 66
Posts: 914
An easy fix would be to put washers between the cover and its mating flange where the affected bolts pass through.
stevef is offline  
Old 30th Dec 2020, 13:29
  #4 (permalink)  
 
Join Date: Mar 2006
Location: Not where I want to be
Age: 67
Posts: 258
I'll be surprised if you cant find an instruction manual using Google. Often these gen sets have engines from specialized manufacturers, Briggs and Straton, Honda etc. You should find the relevant information stamped somewhere on the engines, their web site will tell you where to look.
I've had this happen to me on outboards, gen sets, chain saws and other kit, and it is always a pain in the derrier to assemble without slack in the spring.
Per
Ancient Mariner is offline  
Old 30th Dec 2020, 14:35
  #5 (permalink)  
 
Join Date: Sep 2006
Location: South Oxfordshire
Posts: 618
Originally Posted by stevef View Post
An easy fix would be to put washers between the cover and its mating flange where the affected bolts pass through.
I second stevef's suggestion rather than selling it.

Is the spring mechanism wound tight enough?Just a guess, without knowing how this specific pull cord retracts

Blues&twos is offline  
Old 30th Dec 2020, 15:07
  #6 (permalink)  

Controversial, moi?
 
Join Date: Oct 2000
Location: UK
Posts: 1,595
In my experience what you describe is the result of the housing either distorting and fouling the rotating part of the mechanism sufficiently to prevent the spring from rewinding the cord. Or the housing is clamping down to far and again fouling the mechanism.

Difficult to diagnose further without seeing the unit. But close and detailed examination should reveal the problem.

Where are you located?
M.Mouse is offline  
Old 30th Dec 2020, 15:22
  #7 (permalink)  
Ecce Homo! Loquitur...
Thread Starter
 
Join Date: Jul 2000
Location: Peripatetic
Posts: 11,522
Brighton, on the sarf coast....
ORAC is online now  
Old 30th Dec 2020, 15:24
  #8 (permalink)  
Ecce Homo! Loquitur...
Thread Starter
 
Join Date: Jul 2000
Location: Peripatetic
Posts: 11,522
Is the spring mechanism wound tight enough?Just a guess, without knowing how this specific pull cord retracts
I could take it out again and try and wind it tighter - but it works OK now when the cover containing it is removed from the generator. And of course pulling the handle tightens it further anyway....
ORAC is online now  
Old 31st Dec 2020, 10:05
  #9 (permalink)  
 
Join Date: Apr 1998
Location: Mesopotamos
Posts: 1,529
Perhaps the shoes/pins that spring out are worn (or incorrectly fitted) and grip the crankshaft cylinder at an angle that they don't let go should the motor not fire up. Perhaps the zip cord snags, perhaps the zip cord assembly is cracked and warps when bolted on, but as stevef suggested, perhaps some spacers have gone missing and the assembly is touching the crankshaft cylinder.

You could go old skool by bolting a pulley on to the crank and using a rope.
cattletruck is online now  
Old 31st Dec 2020, 10:21
  #10 (permalink)  
 
Join Date: Oct 2002
Location: West Wiltshire, UK
Age: 68
Posts: 412
I had a similar problem on the pull start of my strimmer. Had me scratching my head for ages, as with the pull start removed it all seemed to work OK. In the end it turned out that the spring inside the pull start spool had slipped, and lost a bit of tension. The fix was a bit awkward, but involved completely dismantling the pull start assembly, removing the spring (very like a clock spring) and trying to estimate just how much preload needed to be on the spring, with the cord fully retracted, to give it enough oomph to retract the cord after being used in anger. It took several goes to get it right. My guess is that they have a jig that winds the spring up with the right preload before it's fitted when they assemble these things, a bit like the gadgets used to pre-wind clock springs during assembly.

Not a difficult job to do, but a bit repetitive, just because it had to come apart every time I needed to try and slightly different preload on the spring.
VP959 is offline  
Old 31st Dec 2020, 10:39
  #11 (permalink)  
Ecce Homo! Loquitur...
Thread Starter
 
Join Date: Jul 2000
Location: Peripatetic
Posts: 11,522
No shoes or pins. Very simple mechanism.

The motor end cover has an integrated metal ring in the centre matching two lugs on the end of the motor.

The pull starter consists of a plastic disc with a groove around the edge for the cable and a extension on the bottom with a groove for the spring - with a cut out on the metal circle for the other end.

You connect the spring to the plastic disk and wind tight enough to fit inside the metal circle, dropping the hook on the end of the spring into the cut out.

No means to increase the tension, the plastic disk turns until the spring has filled the metal circle below.

The plastic disk has another plastic catch which fits on top to engage with the lugs. Pops out when you pull the handle and goes back in when the cable is released (or a turning lug hits the back of it.

The cord is wound around the disk groove which is also covered by the metal circle and emerges from the cut out.

Pull the cord and the lug engages with the motor as the turning disk tightens the spring - let go the cord and the spring unwinds and pulls the cord back inside.

Whole thing is held in place by a large metal washer which fits over the top and bolts down through the centre.

Works perfectly when assembled on the table - but doesn’t retract when bolted to the motor. Start unbolting the cover and after a couple are loosen it zips back in again.

Not sure why - one thought is that the catch is stiff enough that the pressure from the spring isn’t enough to close it when it hits the next lug and it stops, loosening the bolts let’s it slip of the lug. It is greased but I can’t see any way of making it close more easily or increasing the tension of the spring
ORAC is online now  
Old 31st Dec 2020, 14:33
  #12 (permalink)  
 
Join Date: Aug 2006
Location: Lemonia. Best Greek in the world
Posts: 1,701
I had a similar problem with the motor of my leaf blower.

It was hugely frustrating.

The only way I could solve it was by tracking down the precise model of the motor - nothing to do with the "brand" on the blower - hours on Google - and then finding detailed diagrams/instructions, which lead me to a place which had spare parts. I replaced some cheap parts that seemed perfectly OK (!!) and eventually it decided to work.

I hate to think how many times I took that ******* starter assembly apart, and re-assembled it. I understand your frustration. I am not fully sure, but I think the issue was the movement of what you call the lug.
Ancient Observer is offline  
Old 31st Dec 2020, 14:45
  #13 (permalink)  
 
Join Date: Sep 2006
Location: South Oxfordshire
Posts: 618
I had a similar experience with a petrol lawnmower pull cord mechanism after fixing a broken cord.. Lots of taking apart and re-assembling before it decided that it would work again.
Just the nature of the beast by the sound of it.
Blues&twos is offline  
Old 31st Dec 2020, 15:58
  #14 (permalink)  
 
Join Date: Oct 2011
Location: NV USA
Posts: 259
It sounds like you missing a spacer washer or the washer is on the wrong side of the assembly or possibly need to remove a washer. If no spacer fix then it's possible the housing the spool sits into is bent in or has been pressed in distorting it enough to cause interference. When you tighten the recoil onto the motor case the spool is pressing into the crankshaft assembly instead of just engaging with the recoil dogs. Went through this on a Polaris quad bike for several hours, how could something so simple be so impossible?? Google for the parts diagram online and it will show how everything is assembled.
cappt is offline  
Old 31st Dec 2020, 16:51
  #15 (permalink)  
 
Join Date: Aug 2006
Location: Lemonia. Best Greek in the world
Posts: 1,701
We need a model name & number to help any more..............
Ancient Observer is offline  
Old 31st Dec 2020, 19:13
  #16 (permalink)  
Ecce Homo! Loquitur...
Thread Starter
 
Join Date: Jul 2000
Location: Peripatetic
Posts: 11,522
We need a model name & number to help any more..............
Last line of post #1.....

Amazon Amazon



ORAC is online now  
Old 31st Dec 2020, 22:06
  #17 (permalink)  
Ecce Homo! Loquitur...
Thread Starter
 
Join Date: Jul 2000
Location: Peripatetic
Posts: 11,522
If there’s anyone local who wants to try their hand I’m happy to pass it on at cost. Just PM me.
ORAC is online now  
Old 31st Dec 2020, 22:09
  #18 (permalink)  
 
Join Date: Jan 2015
Location: Coasting South
Age: 66
Posts: 70
Pull Starter, how about. "Come here often luv?"
hiflymk3 is offline  
Old 1st Jan 2021, 08:16
  #19 (permalink)  
 
Join Date: Jun 2004
Location: UK Scotland
Age: 59
Posts: 181
Hi Orac
I was in the horticultural machinery business for 30 years as a mechanic on all outdoor equipment
chainsaws, strimmers, mowers, generators etc. First thing, everyone talking about tension of spring.
Provided the spring is not covered in rust and is clean and lightly lubricated, with the starter off machine pull
cord out with handle about halfway and gently let it return towards housing to see handle sits back in
place without slack in rope. This shows you have enough tension in spring. Next, and this is very important
pull cord all the way out and then with cord all the way out grip pulley with other hand and hold it there
then let go of cord and check you can turn pulley another half turn past where the cord has pulled it to.
This is to check you have not over tensioned spring, if you have it will break the spring. If you cannot
get this extra half turn take some tension off spring. As for your description of problem. It could be
cord too thick. Spacers etc assembled wrong, pulley warped or most likely somewhere in transit
it has been stacked on its side and the centre of the starter casing has been pressed in by a few millimetres
not noticeable to the naked eye but enough to cause your problem. Pity I live in Scotland or I would
have had a look at it for you. R
RINKER is offline  
Old 1st Jan 2021, 10:06
  #20 (permalink)  
Paid...Persona Grata
 
Join Date: Aug 2004
Location: Between BHX and EMA
Age: 75
Posts: 237
most likely somewhere in transit
it has been stacked on its side and the centre of the starter casing has been pressed in by a few millimetres
not noticeable to the naked eye but enough to cause your problem.
I second that. A washer under each mounting tab is the easy answer.
UniFoxOs is online now  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.