Jump to content

Ransome/MAG mower issue


Ace
 Share

Recommended Posts

Our ride on Ransome club mower with a MAG engine has a running issue.

Starts and runs great for about 20 minutes then loses power as though the timing/compression/mixture changes. Will restart then just tickover but as soon as you try to increase the revs coughs, splutters and occasionally appears to spit back through the carb. Fuel flow from the tank is excellent and we have changed the plug and carb. Compression seems to be still there when pulling the starter when hot but there will be considerable mechanical drag.  Let it stand for 30 mins and then it will run for say another 10 min then develop the same problem and stop.  Any thoughts?

 

 

Link to comment
Share on other sites

Advert


Don't know that engine but will do some research....

 

Does a club member have a red neon plug cap that flashes when HT passed thru it, and does the engine have CB points ?

 

If fuel direct all ok and compression good, then ignition problem, heat related, coil or condenser/capacitor related.

 

It sounds a bit clattety, cooling system ok ? and fuel cap vent ?

 

What model engine?

 

Link to comment
Share on other sites

Hi Rich,

Many questions I don't know the answer too as yet but will try to find out?

Does a club member have a red neon plug cap that flashes when HT passed thru it, I don't believe so and does the engine have CB points ? ? - looking for a manual.

 

If fuel direct all ok and compression good, then ignition problem, heat related, coil or condenser/capacitor related.

 

It sounds a bit clattety, That's the centrifugal clutch catching just before biting as revs rise cooling system ok ?  Appears to be, no debris and can feel air from flywheel fan over head and fuel cap vent ? Clear 

 

What model engine? Will need to verify.

 

I assume that switch on the bars is a ign kill sw ? Yes

 

Is that a "make" contact to run and a "break" contact to stop ? Not sure

 

Two wires joined to run, contact broken to stop ? as above 

 

Any problems with that switch ? Not that we can tell, won't start when switched to red and kills immediately anytime.

 

4t side valve ...what model ? Need to check but found a manual covering several one of which is ours. 36" ransomes mastiff

 

Our thoughts were heat was affecting something as after 20 mins running fault appears never sooner and after 15 min rest will run properly for another 10 min -etc. etc. However it does spark bright blue when resting but as to timed correctly?

Manual attached.

Well try and find the answers to above and come back.

Thanks, David

 

 

 

346071950_MAG1023103510401045SRLmanuel.pdf

Link to comment
Share on other sites

MH - and fuel cap vent ? Clear 

AG - have the valve gaps been checked? Yes but only when cold as inspection cover requires the exhaust removing. We did think of the inlet valve sticking slightly open in guide when hot. Sometime next week we should be able to borrow a compression tester to compare cold and hot/fault.

Link to comment
Share on other sites

If you've been mowing in cold, damp conditions, the carb could be icing up.   It certainly sounds like fuel starvation which could have several causes and could be something as simple as a bit of floating debris in the tank or feed to the carb.

Edited by Geoff S
Link to comment
Share on other sites

Years ago we had a Ford Escort that did exactly the same, we took the carb apart many times as it was obviously fuel starvation, on the 5th or 6th strip down we found a bit of fluff lodged in a nook (a dead end left by the drilling of the fuel feed), this was obviously moving in use and then blocking the fuel flow, stop the flow and it floated back into it's recess. After the piece of fluff fell out we never had this problem again. I won't say the car ran faultlessly as it didn't, we ended up scrapping it when the drivers seat was in danger of falling through the floor!

 

The other thought, is it a magneto ignition? if so that could be overheating.

Edited by Frank Skilbeck
Link to comment
Share on other sites

When it conks out, ie won't rev beyond a certain revs, establish if it has lost HT, use a red neon plug cap that will flash when HT passed thru, it can be fitted and used when the engine is running, it conks and no flashes at that time means......

 

It could be a but of debris in the carb....being sucked into a jet etc., but that would tend to be random...

 

Establish HT when at working temperature, it may produce HT at the plug in atmosphere, but does it loose HT when warm and at throttle open !

 

A flash of inspiration needed me thinks ?

 

The red neons don't cost much and really save hair loss !

Link to comment
Share on other sites

Thanks guys.

Only used when grass is dry and therefore reasonably warm ! Did the same thing even with the old carb and filter. Carb/fueling was our first thought hence the clean first then a change. Tried pressurising and even lowering by blowing and sucking into the tank - no effect.

Starts easily and as the fault only occurs after 20 min ish running we believe it is heat build up related. Something expanding or breaking down when hot. Particularly as it needs to rest/cool for a good 10 min possibly more before it works again. The longer the rest the longer it will work before stopping again.

Whats confusing is that it will start/idle just not throttle up. 

Can't help think it sounds wheezy with what sounds like pops coming back through the carb as though its blowing back through the inlet valve. Stuck open or timing changed - but it will start/idle.

 

We will see if the compression tester next week helps identify or eliminate anything. 

Link to comment
Share on other sites

Rich - fault occurs when running ie fine then wheeze's/pops then stops. However if you immediately reduce to idle it will stay running, just won't then throttle up so we conclude spark ok. If compression test is ok then a red neon will be next as we are then grasping at straws.  

Link to comment
Share on other sites

How is the plug colour, can you post a picture of the plug firing end ?

 

It's a sv 4t so probably has not grown "whiskers" but it does happen very very occasionally.

 

Clean carb again perhaps ?

 

You sure the fuel tap is not vibrating closed, or semi closed reducing fuel flow ?

 

Anyways, you need to rule out something, the easiest being HT with a red neon plug cap, it fits inline with HT lead and plug, giving a quick visual indication of HT and relative strength, but you may need to give it some shade if using outside. It is a real world engine running test but of kit.

 

I use them lots for petrol engine problem diagnosis.

 

Well worth the money and stops you getting bald and dizzy.

 

Have fun !

Link to comment
Share on other sites

The Ransomes range of mowers are still manufactured at their original site in Ipswich - maybe someone there could help...?

 

They are still the favourite mower for many golf/tennis/bowls clubs so if you have one of these near you it might be that you have someone with experience you could tap in to.

 

Failing that contact them direct - https://www.jacobsen.com/

Link to comment
Share on other sites

Rich - plug colour, light covering of black sooty, probably when we tried opening the choke which just caused it to bog, no whiskers.

Carb changed same fault b4 and after.

Friction tap pointing down for on, no movement.

HT neon cap ordered.

 

B in B - Thanks may do if still stuck.

 

Wincox - manual, no movement but if moved when hot chokes engine.

 

Cuban - Carb changed same fault b4 and after replacement.

 

Robert C - we have the original manual and have also downloaded the parts and Op instructions from your link.

 

Once Neon tester arrives we will try it and the compression tester to see if the results point us in a specific direction.

 

 

Link to comment
Share on other sites

Can't see the manual and parts download images....

 

Does it have CB points ?

 

If yes, how is the gap ?

 

Can the points be seen when engine running thru a flywheel window ?

 

Much arcing going on, bright arcing, and points very white ?

 

I assume the wiring to the kill switch is all good....

Link to comment
Share on other sites

Rich - Parts, manual attached.

Does it have CB points ? Mag with points I believe although not visible through the flywheel without removing recoil starter/mesh cast cover. Look later in the week.

Any problems with that switch ? Not that we can tell, won't start when switched to red and kills immediately anytime.

HT and compression tests later in the week.

Link to comment
Share on other sites

1 hour ago, Brian Lambert said:

Just a thought, is there a capacitor (condenser) across the points? they can fail shorted when hot.

I agree. I don't like guessing without seeing/hearing the engine running, but that would be my prime suspect. The magneto points, coils and condenser all hidden from view are rarely checked.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...