Mend Mountfield SP534 Lawn Mowers

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How can I fix my Mountfield RV150 Lawnmower?

I bought one of these mowers brand new, used it for one season and just like the other guy on this site I am having problems now I have started using it again. Oil levels are fine as is the fuel. The strange thing is it was working fine when I first went back to it but I have cut my grass about 5 times now this year and it seems to have lost all power. Its very difficult to start and if you use the drive at all, or if you push it into grass over 1cm long, it just cuts out. I have changed the spark plug, bled the system and checked all the pipes are clear. I also phoned the mountfield helpline and they advised me to do eveything I had just done. They did say the petrol cap might be on too tight though. I have checked the tank now(plastic) and there are hairline cracks around the seam that are seaping petrol when I fill the tank. Could this be the problem? I have been trying for some time now but I cant find a decent site for mountfield spares (At least not for what I want). Any suggestions would be greatfully recieved.
The model number is SP534,Type ML534TR and I think the part number is HDPE-531-B900
G.

G.Piears
May 2008

Mountfield SP534 Garden Tools, Lawn Mowers Mountfield Rv150 Lawnmower

Hi,
My rv150 keeps backfiring through air filter, then if it starts it will only run for a few seconds then stall ?

Jason
March 2017

my rv150 starts fine when the handle is pulled engaging the kill switch but wont stop running when released. Any ideas

martin
July 2015

hi cant aybody advice me the problem with my mountfield rv 150 it starts ok but will not pick up revs to start cutting just dies

chris
October 2014

same happened to mine and its an easy fix.remove starter case until the carb is exposed,you will see a curved piece of black plastic fixed to the carb by a long spring and a metal wire.Pull the plastic back to its full travel to see if it moves freely,if not spray with wd and twiddle with it until it moves freely

jim
May 2012

i repaired my RV150 split plastic petrol tank with EVO-STIK
EPOXY two part adhesive.Bonds in 90secs.Clean the area well and sand paper down slightly.I glued split area twice to fix it properly.Make sure you leave it overnight before glueing the second time.

G.Egerton
March 2012

hi this is dave_theboat I am having a similar problem and have found the cylinder head gasket is leaking this will give u the symptons you have illustrated

dave_theboat
August 2011

does anybody have the layout drawing for the mountfield rv 150 carb links as I stripped mine and something is not right.

muttsnuts
June 2011

My SV150 was running erratically and was difficult to start, lacking in power. I went through the fuel and spark checks, micro switch function. I noticed that compression when pulling the start cord had fell back and the problem turned out to be the cylinder head gasket had failed. Cost £5-6 to replace and not a difficult job if you have a little mechanical knowledge. Take a photo of the carb springs before you dismantle!

John W
September 2010

I am not so sure about Honda. I bought one after my proper Mountfield died after about 20 years service - no complaints there. The dealer told me that new Mountfields are just as described below. After three years the Honda kept stalling when left idling, and then soon every time to start it I had to strip down the carb and completely retune it. Dealer said I can't expect more because tolerances are so fine to meet emissions regulations and 3 years was a good lifespan. So even spending a lot doesn't help, so then I bough a cr*p Mountfield. I had to have the engine changed after the first time I used it, crankshaft bent, either that or they gave me back a different one. It has run for five years but any metal bits sticking out, handles , levers all fracture and need welding.

John W
September 2010

If you want a good mower that last for years, get a Honda, they are the best on the market. I had one in the US for 12 years and never changed the spark plug, just cleaned air filter and changed oil. Started every time easy. They might be pricey but they are the best.

Kevin
September 2010

Mountfield USED to be good..when they WERE Mountfield !
Now they are a badge stuck on in Italy, just the old CASTEL import junk mower with a new sticker!

John Goodsell
June 2010

These machines use a cheap engine made in China. If you buy cheap mowers like this, you do get what you pay for. The brand name isn't a good guide any more either because often that's all it is - a badge. Better to buy a machine from an independent dealer who will give you honest advice, and have the spares and know-how to keep you mowing.

Blue-eyed boy
June 2010

Replaced head gasket and spark plug for 7 quid. Solved the problem. its only held on by 8 of 9 bolts. With regards to the fuel tank problem, mine has been through 2. Eventually mountfield have finally come up with a modified one that has the pull start in a seperate casing. Happy days at long last

Paul 4274
May 2010

bought new tank, £23. cut side off old and clamped new one to it,, ( leaking tank at seam near filler. ) complete kit£50 well known problem as replacement is in two pieces. will go back to manual mower when this one goes compeatly, deffinitlly made by cowboys

bob fixed it
May 2010

Mine has failed and the head has gone! After reading this i think the only real fix is to find a Briggs and Straton or quality engine which will fit. Any one know an engine?
Dont think I will buy another mountfield, I bought this one because I thought they were a quality mower! how wrong can you be!

John Osborne
May 2010

check the carburtor gasket

twyboy
April 2010

I have an SP534 that I bought in B & Q 2 years ago. It worked fine until recently when I pulled the cord to start it; the cord came out and wouldn't re-coil. I opened it up and discovered the problem. The part that holds the spring is plastic and there is a break at the top of the moulding so instead of re-coiling it just keeps turning inside the moulding. Would anybody with a clapped out SP534 be interested in selling me the part I need?

Dermot Neary, Athlone, Ireland
August 2009

I have had the same problem, together with a very noisy engine when it does run. When I stripped it down I found that the cylinder head gasket had split. I have ordered a replacement part from my local dealer and I am confident that this will cure the problem.

David Mac
August 2009

www.shouldersofshoreham.co.uk
have exploded diags of this mower from the workshop manual. Each part number has a hyperlink

Cav
July 2009

i have had the same problem,and i noticed there are no air holes in the fuel cap like other models.so i put a small air hole in and have had no problems since...bob

robert lewis
May 2009

easy drill a small hole in fuel tank cap not getting air in tank

dundeelad
May 2009

Anyone with a leaky tank plastic or metal?

Nip down to your local Maplins and get a tube of Epoxy Putty.

Method.
After emptying tank, leave it with the top off outside somewhere over night, (the idea being to evaporate all the petrol residue). Then use a bit of sandpaper to roughen up where the holes are and make a good keying surface.

Now kneed a bit of the putty and then push it into hole and leave it for an hour or so.

Result
Should be no more leaks.

Melville Livingstone
May 2009

I have one of these Mountfield mowers from B and Q too. I bought this mower in particular because of the reputation that Mountfield held. I bought the first mower 2 years ago and took it back to B and Q a year later as it was falling apart. They replaced it at the time. I have now had exactly the same problems and B and Q won't replace them anymore and said i have to take it back to Mountfield. I can't find my B and Q receipt now, so i'm stuffed. The wheels have fallen off/ the thing won't start/ the self propelled belt is snapped/ the petrol cap is split/ it has lost a huge amount of power/ it stalls in long grass. It is a complete disgrace and a waste of £300 !

Rob Newbury
April 2009

My one was fine for the first season too and then became impossible to start and wouldn't cut any lenght of grass without cutting out.
I've just checked the cyl head bolts and guess what? all of them but one were loose. A quick tighten and the mower started first pull and just cut 6 " high wet grass! Cant believe I was about to throw it in a skip.
Now all I have to do is sort the missing linkage on the choke. If anyone can advise on the correct dimension for the linkage I'd love to hear from you so I can make one up with a piece of coat hanger. It's the one that controls the butterfly nearest the air filter. Any suggestions?

Ed Collins
April 2009

how much oil to fill it frome new

george
April 2009

Try Mower Magic @ www.mower-magic.co.uk - they do spares for all Mountfield machines. Not everything is listed on their website but they can get everything.

John
November 2008

The problem could be the mixture getting to the engine - on Tecumsehs there is a sliding vane which controls the ingoing air that is not linked directly to the throttle, but works with a system of levers and springs to restrict the air to the correct mixture.

If these springs and levers stick, or get out of adjustment, then the mixture is too weak (or perhaps too strong) and the engine stalls when any more than a little load is put on it.

Try WD40 all over the springs and levers on the intake side (take off the air cleaner first) and it may work, or you may see something obviously stuck or bent.

Ford Macfarlane
August 2008

try the following URL: It may find the part you're after for a reasonable price. I have the same fuel tank issue and am going to give it a go. http://www.mower-magic.co.uk/cgi-bin/sh000001.pl?REFPAGE=http%3a%2f%2fwww%2emower%2dmagic%2eco%2euk%2facatalog%2fMISC_SPARES%2ehtml&WD=mountfield&SHOP=%20&PN=Spare_Recoil_Starters%2ehtml%23a1_21BIN_20MO18550000_2f2#a1_21BIN_20MO18550000_2f2

Redmanc
August 2008

Yup, my plastic fuel tank went exactly the same at the opposite end to the fuel pipe.

I don't believe in disposable lawnmowers so I used a cheap soldering iron with a wide screwdriver iron to 'weld' the seam, then used a glue gun stick to reinforce the weld which I then smoothed over and incorporated into the weld.

Obviously tank has to come off, empty it and clean area as much as possible, leave cap off but please use common sense due to dangers with petrol. I'd also recommend testing the weld prior to reassembling the lawnmower and ensure clip holds petrol tubing firm or replace it like I did

Paul B
July 2008

I too seem to be having all the problems every one else is having, can any one tell me if there is a work shop manual for these cr*p lawnmowers? I must say Mountfield have just lost a customer …. Maybe we should all look for a German mower … anyone know of a make?

sontheweb
July 2008

Hi, I've got a similar problem and have just spent a few hours trying repair the invisible crack in the tank - I have tried solvent cement ( from the local DIY store ) but if this fails, I can reccommend a mastic product called Thioflex 1 ( or 100 )
It is a high quality sealant that is fuel resistant so shouldn't break down when in contact with petrol.
I might also try resealing the joint with a soldering iron which might fuse the two surfaces together

Tony

Southampton

tony oneill
June 2008

If you're still having problems, drop me a line. can sort a replacement engine for you for not much more than the cost of the 80-mile round trip you made to not get it fixed!

The SV/RV150 engines are or Chinese origin, and have no quality control. An earlier Briggs or Tecumseh engine will be a very worthwhile fix.

phil_saunders@bigfoot.com

Phil Saunders
June 2008

I have had no luck at all in tracing spare parts for this mower. I took it back to B&Q in Edinburgh where I bought it and they were very unhelpful there so I have had to take it to a dealer about 40 miles from where I live. He laughed when he saw it and said they are amongst some of the worst mowers ever built! He was able to turn the blade with his finger and said there is no compression at all in the engine so it looks like it’s totally knackered. I still haven’t heard from him if it’s reparable or not. The only good thing I can say about all of this is it came with a 2 year guarantee so I might just get some of the costs back from Mountfield but I won't hold my breath. I realize £300:00 isn't that much for a mower these days but I expected a little more than one season out of it.
VERY disappointing

G. Piears
May 2008

Hi,
I also have a leaky fuel tank, and on removal, discovered the same part number. I am struggling to find a replacement and wondered if you found one? If so, where did you get it? It seems a shame to chuck a perfectly good working mower just because the tank leaks. I did seal the leak for a while with araldite, but that has now gone funny and the leak is worse now!!!

Andy
May 2008

Hi,
I guess if you are having problems getting parts for a recent Mountfield mower, I have no chance for one that my nan bought in 1991 !! It also has a fuel tank leak, looks like small holes caused by corosion (metal tank), it just weeps out. Having said that, it starts after the 3rd pull every time (from cold), 1st time from hot), and has never had an oil change and ony one spark plug. I live next door to my nan so have sort of taken over the mower (and cutting her grass), so am giving it a full service, however, if the old ones on eBay have leaky tanks too, looks like its time for a new mower.

PS, In the past I did have to remove the head after 2 long winters as the valves had stuck open, and it wouldn't start.

Neil

Neil Turner
May 2008

Your symptoms indicate a blown head gasket. Sometimes you can get away with removing the head, putting grease on both sides of the gasket (if it's stuck to the block, don't prise it off), and re-assembling. The grease will carbonize, and seal the leak. Quality control on these is so poor it's likely that it left the factory with loose head bolts. If that cures the problem - even if only for a couple of hours - you know you will need a new gasket (one of the few spares available for these engines).

phil_saunders@bigfoot.com

Phil Saunders
May 2008

Many thanks Richard for your speedy reply. I did have a look at that when I took the carb to bits. I have probably destroyed any chance of getting it repaired on its warranty but I couldn't help myself especially as it was working fine two days before hand. I have just had another go at it and the problem appears to be getting progressivly worse. Not much of an engine if its only capable of lasting one season eh.

G Piears
May 2008

The leaky fuel tank is a common problem. I was lucky to find a good used one, but otherwise 5 Star Adhesives might advise. The lack of power is usually due to the speed regulator. If you take off the fuel tank, you will see a vane which closes the throttle if the engine fan speeds up, and opens it if it slows down under load. It's very crude, and tends to stick, so might be worth a look.

Richard
May 2008