DIY Forum

 

Ultimate HandymanUltimate Handyman on Pinterest

 

DIY Forum/Home improvement advice forum

 

 

A-Z CONTENTS | DISCLAIMER | DIY VIDEO | HOME | SAFETY FIRST | FORUM RULES

It is currently Tue Sep 18, 2018 3:22 pm
Visit Hilti


Time zone: Europe/London [ DST ]




 

 


Post new topic Reply to topic  [ 17 posts ]  Go to page 1, 2  Next
Author Message
PostPosted: Sat May 05, 2018 5:29 pm 
Offline
Newly registered Member

Joined: Sat May 05, 2018 5:16 pm
Posts: 9
Has thanked: 0 times
Been thanked: 0 times
My Mountfield HP185's engine is surging when running, it's one of the ones with a plastic carb which has no adjustment screws on it at all anywhere.

Things I've done so far:

Stripped and cleaned carb
Put fresh fuel in
Cleaned Air filter
Gapped spark plug
Reset governor position (as per Briggs & Stratton instructions online)

When running I can see the governor arm constantly moving back and fourth which is causing the carb to constantly open and close. I disconnected the governor from the carb to see how the engine runs and for some reason when the linkage on the carb is manually pushed to the fixed idle stop the engine cuts out, so I'm wondering if because under normal operation the carb is pretty much supposed to idle that because mine won't idle the governor keeps kicking in and opening the carb and upping the revs momentarily then it just keeps getting stuck in a loop of opening and closing the carb, hence the surging.

So, am I right in thinking that with the carb linkage pushed up the the fixed stop that the engine should be idling quite happily and not cutting out?

Temporarily I've added my own adjustable stop so when it's idling it doesn't cut out but this isn't the best fix and isn't how it is supposed to be so any advice on anything else I can take a look at would be great.

FYI there is definitely no adjustment anywhere on the carb or the carb linkages.

This is the mower:

https://www.screwfix.com/p/mountfield-hp185-45cm-125cc-hand-propelled-rotary-petrol-lawn-mower/1323f

And the carb:

https://www.outdoorspares.com/Outdoor-spares-lawnmower-spare-parts/Mountfield-Lawnmower-spare-parts-GGP/Mountfield-mower-By-Model/Mountfield-petrol-lawnmower-model-sp185-hp185/Genuine-Briggs-Stratton-300E-450E-Replacement-Carburettor-Part-No-591979-595656

And my temp fix:

The screw prevents the carb from closing all the way when at idle
Image


Share on FacebookShare on TwitterShare on DiggShare on DeliciousShare on Google+
Top
 Profile  
Reply with quote  
PostPosted: Sat May 05, 2018 5:44 pm 
Offline
Senior Member

Joined: Fri Jan 20, 2006 5:51 pm
Posts: 8190
Location: Essex
Has thanked: 589 times
Been thanked: 1717 times
I found that the governor spring is usually responsible for surging. They tend to fatigue out over time and I tinkered with one by shortening it a bit by putting a fresh bend in the spring end. I view mowers as disposable these days and I put £5 a month away for replacement. As soon as it plays up usually four or five seasons, I replace it. I ponced around replacing a carburettor once and got another few months out of a mower before something else went. So the £60 I spent was a third of a new one. Same rule applies to washing machines.

DWD

_________________
Painting with BIN


Top
 Profile  
Reply with quote  
PostPosted: Sat May 05, 2018 5:46 pm 
Offline
Newly registered Member

Joined: Sat May 05, 2018 5:16 pm
Posts: 9
Has thanked: 0 times
Been thanked: 0 times
dewaltdisney wrote:
I found that the governor spring is usually responsible for surging. They tend to fatigue out over time and I tinkered with one by shortening it a bit by putting a fresh bend in the spring end. I view mowers as disposable these days and I put £5 a month away for replacement. As soon as it plays up usually four or five seasons, I replace it. I ponced around replacing a carburettor once and got another few months out of a mower before something else went. So the £60 I spent was a third of a new one. Same rule applies to washing machines.

DWD


I have actually ordered a new spring which hasn't arrived yet but after finding out that the carb won't run with its linkage in the idle position I suspect that maybe there is an issue with the carb itself.


Top
 Profile  
Reply with quote  
PostPosted: Sat May 05, 2018 5:50 pm 
Offline
Senior Member

Joined: Fri Jan 20, 2006 5:51 pm
Posts: 8190
Location: Essex
Has thanked: 589 times
Been thanked: 1717 times
Baring in mind what I said above, how old is it?

DWD

_________________
Painting with BIN


Top
 Profile  
Reply with quote  
PostPosted: Sat May 05, 2018 5:52 pm 
Offline
Newly registered Member

Joined: Sat May 05, 2018 5:16 pm
Posts: 9
Has thanked: 0 times
Been thanked: 0 times
dewaltdisney wrote:
Baring in mind what I said above, how old is it?

DWD


It's 3 years old but runs like a dream other than the surging. It gets yearly oil and filter changes and blade sharpening.


Top
 Profile  
Reply with quote  
PostPosted: Sat May 05, 2018 5:52 pm 
Offline
Newly registered Member

Joined: Sat May 05, 2018 5:16 pm
Posts: 9
Has thanked: 0 times
Been thanked: 0 times
I'll see what happens when my new spring arrives.


Top
 Profile  
Reply with quote  
PostPosted: Sat May 05, 2018 6:16 pm 
Offline
Senior Member

Joined: Fri Jan 20, 2006 5:51 pm
Posts: 8190
Location: Essex
Has thanked: 589 times
Been thanked: 1717 times
Yes, it should last longer than 3. The spring might do it. Worst is when the carb gets gummed up jets.

Lets us know how you get on. There is nothing a good sledge hammer cannot cure :lol:

DWD

_________________
Painting with BIN


Top
 Profile  
Reply with quote  
PostPosted: Sat May 05, 2018 6:18 pm 
Offline
Newly registered Member

Joined: Sat May 05, 2018 5:16 pm
Posts: 9
Has thanked: 0 times
Been thanked: 0 times
dewaltdisney wrote:
Yes, it should last longer than 3. The spring might do it. Worst is when the carb gets gummed up jets.

Lets us know how you get on. There is nothing a good sledge hammer cannot cure :lol:

DWD


lol. I've poked a small rod in all the jets and holes in the carb to clean them out.


Top
 Profile  
Reply with quote  
PostPosted: Sun May 06, 2018 6:50 am 
Offline
Senior Member
User avatar

Joined: Fri Sep 14, 2007 7:45 am
Posts: 484
Location: Suffolk
Has thanked: 0 times
Been thanked: 19 times
Had the same problem with my Webb mower which has the same B&S engine. The spring stretches I ordered a new spring and being a tight wad bent the old spring to the new ones shape. The mower now runs well.

Just a small point do you drain the fuel tank at the end of each season? Now days I use fuel stabiliser which seems to help.

HTH

Peter C

_________________
The end justifies the means


Top
 Profile  
Reply with quote  
PostPosted: Sun May 06, 2018 6:14 pm 
Offline
Newly registered Member

Joined: Sun Dec 18, 2016 5:23 pm
Posts: 79
Has thanked: 3 times
Been thanked: 18 times
If it's not the spring- clean the carb again.Not just poking the holes through but a thorough soaking in carb cleaner and spraying through. Leaving any old fuel in over winter does this, classic issue.

As above, best to treat mowers as disposable items these days. Older B&S engines would run forever with a new diaphragm every few years, deck would rust out long before the engine died. Not convinced by the newer plastic carbs. Even if they last, 5 years from Mountfield deck is good going these days


Top
 Profile  
Reply with quote  
PostPosted: Sun May 06, 2018 6:24 pm 
Offline
Senior Member
User avatar

Joined: Wed Sep 10, 2008 4:58 pm
Posts: 3271
Has thanked: 839 times
Been thanked: 368 times
There's stuff you can buy from Halfords that you can put in the fuel when running that's supposedly meant to clean the carbs out.

I used it on an old strimmer last year and it worked a treat.


Top
 Profile  
Reply with quote  
PostPosted: Mon May 07, 2018 4:03 pm 
Offline
Newly registered Member

Joined: Sat May 05, 2018 5:16 pm
Posts: 9
Has thanked: 0 times
Been thanked: 0 times
columbiers wrote:
If it's not the spring- clean the carb again.Not just poking the holes through but a thorough soaking in carb cleaner and spraying through. Leaving any old fuel in over winter does this, classic issue.

As above, best to treat mowers as disposable items these days. Older B&S engines would run forever with a new diaphragm every few years, deck would rust out long before the engine died. Not convinced by the newer plastic carbs. Even if they last, 5 years from Mountfield deck is good going these days


Not supposed to use carb cleaner on plastic carbs as they warp.


Top
 Profile  
Reply with quote  
PostPosted: Mon May 07, 2018 4:04 pm 
Offline
Newly registered Member

Joined: Sat May 05, 2018 5:16 pm
Posts: 9
Has thanked: 0 times
Been thanked: 0 times
peter c wrote:
Had the same problem with my Webb mower which has the same B&S engine. The spring stretches I ordered a new spring and being a tight wad bent the old spring to the new ones shape. The mower now runs well.

Just a small point do you drain the fuel tank at the end of each season? Now days I use fuel stabiliser which seems to help.

HTH

Peter C


I'm pretty sure its the spring, my new one should arrive soon.


Top
 Profile  
Reply with quote  
PostPosted: Mon May 07, 2018 6:41 pm 
Offline
Newly registered Member

Joined: Sun Dec 18, 2016 5:23 pm
Posts: 79
Has thanked: 3 times
Been thanked: 18 times
Ripp wrote:
columbiers wrote:
If it's not the spring- clean the carb again.Not just poking the holes through but a thorough soaking in carb cleaner and spraying through. Leaving any old fuel in over winter does this, classic issue.

As above, best to treat mowers as disposable items these days. Older B&S engines would run forever with a new diaphragm every few years, deck would rust out long before the engine died. Not convinced by the newer plastic carbs. Even if they last, 5 years from Mountfield deck is good going these days


Not supposed to use carb cleaner on plastic carbs as they warp.


Yep, heard people say that before- and indeed some plastics can be damaged by it. Can only speak from experience but i've done hundreds of these with no issues. I guess someone somewhere may have had an issue with a B&S carb but i've never heard or seen it.


Top
 Profile  
Reply with quote  
PostPosted: Mon May 07, 2018 6:45 pm 
Offline
Newly registered Member

Joined: Sat May 05, 2018 5:16 pm
Posts: 9
Has thanked: 0 times
Been thanked: 0 times
columbiers wrote:
Ripp wrote:
columbiers wrote:
If it's not the spring- clean the carb again.Not just poking the holes through but a thorough soaking in carb cleaner and spraying through. Leaving any old fuel in over winter does this, classic issue.

As above, best to treat mowers as disposable items these days. Older B&S engines would run forever with a new diaphragm every few years, deck would rust out long before the engine died. Not convinced by the newer plastic carbs. Even if they last, 5 years from Mountfield deck is good going these days


Not supposed to use carb cleaner on plastic carbs as they warp.


Yep, heard people say that before- and indeed some plastics can be damaged by it. Can only speak from experience but i've done hundreds of these with no issues. I guess someone somewhere may have had an issue with a B&S carb but i've never heard or seen it.


Fair enough. I gave mine a good clean with an air line.


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 17 posts ]  Go to page 1, 2  Next

 

 




Similar topics
   

Time zone: Europe/London [ DST ]


Who is online

Users browsing this forum: No registered users and 0 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Visit Solent plastics


 

 

 

News News Site map Site map SitemapIndex SitemapIndex RSS Feed RSS Feed Channel list Channel list
ultimatehandyman privacy policy

Contact

 

Powered by phpBB® Forum Software © phpBB Group

phpBB SEO