Problems getting a B&S 13HP going. New-to-me old ride on mower.

Hi All,

Picked up a ride on mower the other day and would love to get it going. The battery is completely dead but it has a pull-cord start also. I have managed to hear the engine run for about 1-2 seconds in my attempts but then it just cuts out again.

What I have tried:

Jump starting - it tries to start and will run for a second with some easystart sprayed direct into the carb but thats it.

Pull cord starting - same deal, will try to start with a bit of easy start in the carb but then nothing.

Changed spark plug, have tried with choke in both positions. No change.

I replaced a dodgy fuel hose and put fresh fuel in, drained the bowl on the carb at the same time. Im no mechanic though and whilst I can navigate a tool set, I don't really know where to start.

Its a Laser L80 ride on, which seems very similar to some of the Westwood machines. The engine is a 28M707 I think, 13hp Briggs & Stratton. The carb is a LTM model 5-4993

Any help/ideas/hints would be appreciated.

 

Take the bowl off the carb and see what kind of gunk and garbage is in there. Maybe you'll be lucky and it's just a stuck float, or it might be full of crud and varnish and require extensive cleaning to get it going.

 

Thanks for the reply. I have taken the bowl off and there didnt seem to be any visual gunk, the float appears to operate correctly. I need to get my compressor working before I can try and blow through any lines.

Would soaking the carb overnight in thinners help to remove the varnish build up?

I cant find a replacement carb that is an exact match, but have ordered one which seems to be a more modern replacement. For £20 it was cheaper than buying a rebuild kit and doesnt depend on my skills as much, would still like to give cleaning this one a go though if the solvents wont kill it.

 

Thinner won't help anything, you'll need carburetor cleaner. You can buy it in a spray can at any auto parts store. If yours is not gummed up, spray cleaner is likely all you need. I don't think there's any reason to try to replace the carb, just leave yours on there. Is any gas coming into the bowl area? If not, that's the problem. Does it have a shutoff valve in the fuel line?

 

Yeah there's fuel getting into the bowl, and no shut off on the fuel line.

I'll pop out tomorrow and try and pick up some carb cleaner and give that ago first. The spark plug does appear to be wet when I pull it out as well if that means anything

 

Well, if it's starting up on the fuel you give it and running just long enough to burn it off, then it's not getting enough fuel. That pretty much leaves the carb. Make sure the jets are clear, and unless you have bad parts, you probably won't need a kit or replacement. Just cleaning. Pick up a torch tip cleaner from a hardware store or lowes/HomeDepot and run it through the main jet going up the center of the carb, the little hole in the side of the part that drops down into the bowl, and make sure the fuel shutoff solenoid is working if it is equipped with one (that mower originally wasn't but I see a newer engine on there so anything is possible).

 

ITS ALIVE!!!!!!!!!!!

Ish...

Gave it a good clean with just a can of carb cleaner and it fired up. I was so surprised by it doing so that I panicked a bit and pinched the fuel hose to stall it. There were some sparks coming from around the exhaust muffler which was odd and a fair bit of oil spraying out of the exhaust too.

I'm hoping that this is just gunk that the engine will burn off if I leave it running for a bit but it was dark and so I'll leave it til the morning before I try again. 30ft plumes of smoke at 10pm worries the neighbours. A big confidence boost in the engine though and really hoping I can get the grass cut soon!

There isn't a fuel shut off solenoid on the carb on this engine either, just a bolt in the bottom of the bowl. I'll try and pick up a torch tip cleaner next time I'm at the hardware store as well.

Could the sparking be because there is no battery in it at the moment and so no ground, or is that something I made up in my head?

 

I have a 13 HP B&S Engine that has been very reliable until 2 weeks ago when the float needle stuck open while sitting over night and about a quart of gas migrated from the fuel tank into the crankcase.

That engine (mine) was flooded, and I had to drain BOTH the diluted crankcase oil and my fuel lines.

I mention this because you never mentioned what the condition of the crankcase oil was when you began resuscitating this engine, and I'd worry a mite about whether your "sparking" indicates that you are suffering the beginnings of something similar with your float needle and thinning oil.

 

In all honesty other than checking the level I haven't done any examining on the oil.

Is there a simple test that will determine if there is fuel in the oil? Or is it a case of just drain and replace anyway?

 

You'd probably be able to smell gasoline soon . . . . and the oil would be much thinner than it was the last time you looked.

Since you didn't look at the condition, one test would be to examine the dipstick to ascertain whether the oil level is creeping up WITHOUT any explanation, while the gas in the tank is mysteriously disappearing.

 

Oh i see, so were talking about a whole lot of fuel migrating then, not just a little bit. I will have a good look tomorrow.

Will it run like this, or should I not even attempt it until I figure it all out? I can order a new needle and seat for the carb if its needed but it will take a few days to get here.

 

It's probably not even your problem at this point.

My engine(s) will run at the beginning of this condition (a dangerous situation) . . . . but after a short period of time, the combustion chamber is filled with gas and no more ignition occurs. (The gasoline has to travel from the carburetor past the intake valve and the piston rings to load up the crankcase. That process can be rapid or long drawn out depending on the position of the intake valve).

Smell your dip stick to be on the safe side . . . . otherwise, I'd conclude that the sparking you witnessed is just flecks of built-up carbon and the gunk you mentioned earlier.

I've had this problem occasionally with Tecumseh engines in the past, and maybe all gravity feed fuel systems stand to experience it . . . . but this is the 1st B&S engine on which I have had to be concerned about the gas migrating like that. A manual fuel shut off, or the fuel solenoid can serve as a bit of an insurance policy.

Hopefully you won't smell any gasoline on your dipstick.

By the way, my 13HP B&S engine is a 28M707-0137-01 branded under the Craftsman name. It is now the 3rd engine to be driving my 1973 AMF/Murray/Dynamark/Noma/AYP Mower . . . . has a catchy Red plastic shroud over it.

 

So what was the oil level?
It can be difficult to smell gas in the oil on the dip stick, at least with my aging olfactory senses. If it is over full or pull the spark plug and spin the engine, if it spits anything out then very likely oil is fuel contaminated. Would not hurt to change it any way but if any of these signs, then it NEEDS to be changed.
You also might look at the muffler and cooling fins of the head and look for signs of an oil leak that may have built up and will take time to burn off or can be washed off.
A good way to test the carb for needle valve leaking:
Remove and clean, also remove the float/pin/needle valve and clean.
Reassemble the carb and mount on the studs to the engine leaving it loose from the intake. Connect the fuel supply and give it up to 5 mins watching for fuel to begin leaking. If it does leak this will prevent contaminating the oil again. If it does leak then you have a needle/seat issue.
Extensive use of starting fluid, carb cleaner or any other priming to attempt it to start might well be the cause also.

 

Vermont:

Mine is the 28M707 too, ill have a sniff of the dipstick and will probably drain the oil and replace to be safe anyway. Theres a part of me that just wants to leave it running for 5 minutes and see if it burns off and then theres the paranoid non-mechanic part of me that is worried about big explosions and setting the barn on fire!

BFHFixit:

The oil level was spot on - although now i think of it i remember thinking it was dark at the bottom of the dipstick and a little lighter at the top. Could that be fuel sitting on top of the oil doing that?

The muffler was where a lot of the oil was spitting out, in fact it seemed to be coming out of the two bolts that holds the muffler direction shield thing in place as well.

Ive been trying pretty hard with the easy start, and i ran it straight after a hit of carb cleaner so hopefully that could be it.

---

I guess im just glad it runs and is therefore worth putting some effort in to do it all properly. With limited knowledge, tools and experience every thing i try usually means a £10 tool here, a £20 part there and it adds up pretty quick without ever knowing if its going to be worth it. The advice here has been invaluable - thanks everyone!

 

Without knowing the oil level before beginning, I would change it out and then determine. Test the carb as I mentioned and at least you will have that much more info to go on.

Not sure what that thing is but reminds me of an old murray...might be a great mower if it fits your needs.

 

From what I gather it was made by a company in Bristol, UK (only a few miles away from me) and it looks like they used a lot of Westwood parts.

It should do me fine, I dont have much grass to cut, but enough to make doing it with a pushalong a tedious chore.

Ill do that carb test and see what that shows too.

 

I have today drained the oil (need to get a drain kit for next time - yuk). It smelt a little of fuel, but i couldnt be sure. I have a few litres of oil in stock so will probably flush it and then refill it tomorrow.

I also dismantled the carb again and cleaned it out properly, ensuring that every hole was blown through and that it was perfectly clean. There was a little bit of crud in the bowl depsite cleaning it before so I have ordered a fuel filter, stop tap and will flush the fuel tank out too I think just to be 100% positive it doesnt crud up again.

I removed the muffler as im 90% sure this is the source of the sparking. I dont really want to replace it if I dont need to, but has anyone used the fire method of cleaning the carbon out of them? Does it work?

Looking through the muffler hole into the exhaust port its pretty gummed up and black inside - no idea if its normal or bad. Is there a de-coking solution I can add to clean the engine out or is it a case of just let it burn off?

More parts, more waiting, but hopefully I will be able to post a video of it purring soon!

 

Wow that does look the the old first rider mower which was a DYNAMARK brand name that my dad bought in 73 or 74...
One of the first ones that my Paran taught me to work on also.

You posted the model of the engine. What about the TYPE and CODE numbers. I am curious about the year it was made.

 

Im not sure about the year, the engine isn't the original, that would have been a Honda GV400.

If I had to guess I would say its mid-80's but i could be way off the mark.

 

Just fire up the engine and let it burn off the muffler out in the driveway. Once it's running right it should burn off during the first use.

 

Put everything back together and it ran!

It took a shot of easy start to get it going but once it was running on full choke i left it for a minute or two and the smoke died down. Took it for a couple of laps of the front yard for 5 minutes and it seems to move forward ok in all gears.

Tried engaging the blades but just burning rubber and no movement - these could be seized solid I really need to get the deck off and take a proper look.

The sparks seemed to be coming from the blade belt guide rubbing against the lower pulley. Ill need to adjust this properly but pulling it out of the way seemed to stop them. The sparks from the exhaust stopped after a few seconds too.

I was hoping that after a few minutes of warming up and driving around it would let me turn the choke down a bit and run quieter - but it just stalls on anything but full choke. Once its stalled it wont restart without another hit of easy start - so still not running right but glad it moves!

Im not happy with the fuel line still, need some better clips and a different size pipe I think. Any ideas on why I cant turn the choke down would be appreciated though.

Heres a very short video of it running and then stalling (in case you've never seen that lol)

https://youtu.be/z5oUlyMCQwI

 

You still have a carburetor restriction, it needs a more thorough cleaning.

 

Figured that might be the case. Im going to give it another go once i get a tip cleaner. Also now I think about it I didnt take the idle screw out and blow through that. :doh:

Is it just me or does the whole rubber fuel hose crossing above the hot exhaust seem a bit mad? I feel like there should be a heat shield or something.

 

Regarding the routing of the gas line, my 28M707-0137-01 has its fuel coming in from the dashboard as I have a separate gas tank mounted where your battery is located.

Now that you noticed this design flaw, you have a responsibility to re-route the line around back . . . . I don't think Briggs would have routed it over the muffler unless it was a special request for export to the Brits.

I don't have that integrated fuel tank like yours. I'm also lacking the recoil starter that I think you said you've utilized in this effort.

Yours must have a Cast Iron Sleeve in the cylinder as wel. Mine was manufactured in 1993 and runs like new. I'm hoping that it's the 3rd and last engine that my 1973 mower will required.

 

Ill do that then, ill run the line around the rear of the engine and maybe stand it off a bit too. New hose and clips arrived this morning so perfect timing.

Think this unit is the 28M707-1133-E1. I have seen them without the recoil unit too but its come in very handy this week! All last year I was having to push my siimplicity mower 'back to base' as the battery wouldnt hold a charge to jump start it, so I can see how the recoil start comes in handy.

 

Just wanted to say a big THANK YOU! to everyone who helped in this thread.

Today I cut the grass!

The replacement carb arrived and the rebuild kit hasnt yet so I installed the carb and set the old one on the shelf for a good scrub at a later date. Ran a proper fuel hose around the back of the engine and put some half decent pipe clips on. The governor link was a little bent up so used some reference pics to get it back in line and it fired straight up - no easy start - just pure purring goodness.

Putting the choke in drops the revs nicely, and while the idle probably needs adjusting a bit to stop it stalling when the choke is completely off it sounds a million times better.

The smoking on the belt I thought was being caused by a stuck pulley or damaged bearing but when I took the deck off I noticed one edge had been banged pretty hard and was obstructing the blade. I used a calibrated fine adjustment device to whack it back out of the way and the blades spun freely.

Cut about half the yard before the fuel was running low so will pop out later to fill up the jerry cans and be back in business. The only thing left to do now is give it a wash and see if a bit of polish makes that brown shine lol, oh and fix the electrics because I think those lights are awesome!

Thanks again - e-beer for everyone -

 

Congratulations on that success.

Your "Laser" mower looks quite like my 1973 AMF/Dynamark/Noma/AYP/Murray/TurfMaster did early in its life.

I say it that way because after I replaced the 1st engine (8 HP B&S) with a 10 HP Tecumseh), the Hood wouldn't fit, so my Wife gave the hood away to the scrap metal dealer.

Then, 20 years later, when I replaced that Tecumseh with the 13 HP B&S, I looked around for the Hood . . . . because it would have fit over this engine; but too late.

This week I'm rebuilding the Steering Gear, and had to "carve" a new bronze lower steering wheel shaft bushing out of a larger bronze item because that part is now obsolete.

Keep that puppy greased and it will serve you well. Besides for engines, I've replaced the Deck twice now, rebuilt the transmission, replaced front wheel spindles, seats, tires, countless pulleys, and lots of wiring . . . . but it's now like an old friend.