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Hi,
I have a lawn boy, model #5236 which is giving me trouble starting. It has been lying unused for about 10 years but yesterday when I started it it fired after several attempts. When I switched it off and tried starting it the second time, it refused. I thought the problem was the spark plug and plug wire. So today, I bought a new plug and replaced the plug wire. When I tried starting it, it fired right up! After fiddling with the air/fuel mixture knob, it died. I tried repeatedly to start it the second time and after 20 or so attempts, it fired up again. I mowed a section of the lawn for about 20 minutes and then the thing died on me. Upon checking, I realized that it had run out of fuel. I filled the tank and tried starting it again. At times, it almost seemed to start but then it quickly died away. I gave up starting it after bruising my hands.

What could be the problem with it?

My procedure for starting it:
1. Prime it 10 times
Pull the cord
FAIL
2. Adjust the idle knob (not sure if this is the idle knob but it is the smaller of the two knobs)
Prime it 10 times
Pull the cord
FAIL
3. Repeat ad infinitum

Check your top and bottom oil seals aka crankcase seals, a lot of times when a motor sets unused for any length of time especially ten years or better the rubber becomes hard on the seals and they lose there ability to seal properly. Lawnboy's are particularly picky when it comes to crankcase pressure any leaks in the crankcase will definatly effect the running and starting!! Also you might try cleaning the carb and rebuilding it, any gas at all left in the carb for that length of time is sure to have gummed something up!!

robinb66 said:

Check your top and bottom oil seals aka crankcase seals, a lot of times when a motor sets unused for any length of time especially ten years or better the rubber becomes hard on the seals and they lose there ability to seal properly. Lawnboy's are particularly picky when it comes to crankcase pressure any leaks in the crankcase will definatly effect the running and starting!! Also you might try cleaning the carb and rebuilding it, any gas at all left in the carb for that length of time is sure to have gummed something up!!

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Thanks! Will do that once I get a technician to look at it as I have no idea how to open the carb. Funny thing, after letting it lie overnight, this morning it fired up with the first pull! Weird...

I'm curious... how did you get a Lawn-Boy in Kenya? Did you import it?

Do you have ethanol mixed with the gasoline in Kenya? If so, it's more likely that stale fuel may be a factor in this problem.

Based on what you've said so far, I think a dirty and clogged carb is the most likely problem. Is the carb metal (good) or plastic (bad)?

Also, there may be a fuel filter in the tank -- at the valve. Can you see it? If it's clogged, that could be the problem.

For future reference, you have a D-series engine. You can read about that engine in many threads in this forum -- you may want to do a search and read up.

Two-Stroke said:

I'm curious... how did you get a Lawn-Boy in Kenya? Did you import it?

Do you have ethanol mixed with the gasoline in Kenya? If so, it's more likely that stale fuel may be a factor in this problem.

Based on what you've said so far, I think a dirty and clogged carb is the most likely problem. Is the carb metal (good) or plastic (bad)?

Also, there may be a fuel filter in the tank -- at the valve. Can you see it? If it's clogged, that could be the problem.

For future reference, you have a D-series engine. You can read about that engine in many threads in this forum -- you may want to do a search and read up.

Click to expand...

Hehe, my grandfather bought it way back in the 70's, no idea if he bought it new or from another person.
Ethanol mixed with gasoline?? I thought it was oil mixed with gasoline! I bought oil and petrol/gasoline and mixed the two in the ratio 32:1 (as was written on the side plate).
The carb is made of metal but I haven't yet opened it as I am still new in this. Once I get a technician, we'll look at it and I'll report back. The fuel filter (if it's that thing located in the corner of the fuel tank with small holes) seems to be ok as the fuel flows out when I disconnect the black fuel pipe below the tank.
Is it possible that a dirty and clogged carb could refuse to fire up when it's hot (as I've noticed that the mostly problem occurs when the mower is hot) and operate normally when it's cold?
Anyway, thanks guys for your feedback, I'll make sure to report back on any new developments. Will also probably attach a pic or two later to make it easier to spot the problem.

rev20 said:

Hehe, my grandfather bought it way back in the 70's, no idea if he bought it new or from another person.
Ethanol mixed with gasoline?? I thought it was oil mixed with gasoline! I bought oil and petrol/gasoline and mixed the two in the ratio 32:1 (as was written on the side plate).
The carb is made of metal but I haven't yet opened it as I am still new in this. Once I get a technician, we'll look at it and I'll report back. The fuel filter (if it's that thing located in the corner of the fuel tank with small holes) seems to be ok as the fuel flows out when I disconnect the black fuel pipe below the tank.
Is it possible that a dirty and clogged carb could refuse to fire up when it's hot (as I've noticed that the mostly problem occurs when the mower is hot) and operate normally when it's cold?
Anyway, thanks guys for your feedback, I'll make sure to report back on any new developments. Will also probably attach a pic or two later to make it easier to spot the problem.

Click to expand...

If you haven't heard about ethanol in the gasoline, I'd guess it's probably not in there. You're lucky -- that's just one more thing that can cause a problem with these engines.

If the problem only occurs while it's hot, then it's more likely that some kind of crankcase seal problem (as robin66 pointed out) could be it. That could be the gasket between the reed plate and the crankcase (relatively easy to fix) or the crankcase seals (harder to replace but I'd bet almost all engines that old need those -- but it may not be the critical problem.)

Cleaning the carb is still the first thing that I'd do if I were you.

I have attached some pics of the mower. Could you please tell me where the crankcase seal/gasket is located?

rev20 said:

I have attached some pics of the mower. Could you please tell me where the crankcase seal/gasket is located?

View attachment 19700

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The seals that robin66 referred to are round, hard rubber rings (#40 on the diagram below) that go around the crankshaft. The gasket (#41 on the diagram below) that I was talking about in a previous post is located between the crankcase (#29) and the reed plate (#42).



You might want to check out this page with links to a good Lawn Boy manual. It covers your D-Series engine.

I forgot to say that there are two crankshaft seals (#40) -- one on top, one on the bottom.

I'm very curious about how your Lawn Boy got to Kenya. If you talk to a mechanic or parts dealer, could you ask if they were ever imported?

On the metal tag with the model number, is there a city name -- where the mower was made?

you might have a second look at that coil too,i see the outer coating cracked,that could be a reason it dies after a little time of running,after it dies after running check for spark,if no spark immediately after it dies its a bad coil

Two-Stroke said:

I forgot to say that there are two crankshaft seals (#40) -- one on top, one on the bottom.

I'm very curious about how your Lawn Boy got to Kenya. If you talk to a mechanic or parts dealer, could you ask if they were ever imported?

On the metal tag with the model number, is there a city name -- where the mower was made?

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Sorry for the late reply. On the plate is written "Outboard Marine Corp. Bruges Belgium". I doubt if they were imported back then, most likely he brought it home with him (he used to tour different countries) from Europe.
A mechanic will be coming to look at it this Thursday, so we'll see how it goes.

rev20 said:

Sorry for the late reply. On the plate is written "Outboard Marine Corp. Bruges Belgium". I doubt if they were imported back then, most likely he brought it home with him (he used to tour different countries) from Europe.
A mechanic will be coming to look at it this Thursday, so we'll see how it goes.

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Thanks for that bit of info. I never knew that LBs were made in Bruges. I've been there a couple of times and it's a beautiful old city.

Please ask the mechanic if he sees many of those.

Power lawnmowers in Kenya are not very common. The only ones I have seen in the stores are what here in the states we would consider entry-level Briggs & Stratton engined ones, selling for about twice the cost (when you convert Kenya shillings to dollars) as they do here. It appears you are missing the shroud on the top, or perhaps you took it off for the photo? I doubt if you have ethanol in Kenya. My wife is from Kenya and I have traveled there several times.

Two-Stroke said:

Thanks for that bit of info. I never knew that LBs were made in Bruges. I've been there a couple of times and it's a beautiful old city.

Please ask the mechanic if he sees many of those.

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Hi there,
I did take the lawn boy to the mech. The problem turned out to be a leaking seal and jammed/stuck rings (that's what he called them). We realized they were stuck coz they weren't moving at all when the blade was turned by hand (with mower upside down and exhaust plate removed). For the seal, there were oil/gasoline drops on the exhaust plate which indicated that it was leaking. The whole thing will take me back close to $100 which is why I have to wait for the end month so I can fix them. :wink:
Concerning these types of mowers in Kenya, the mech had no idea where they came from. He also noted that there are very few around left.
BTW, you seem interested in Kenya, are you from here yourself?

Phototone said:

Power lawnmowers in Kenya are not very common. The only ones I have seen in the stores are what here in the states we would consider entry-level Briggs & Stratton engined ones, selling for about twice the cost (when you convert Kenya shillings to dollars) as they do here. It appears you are missing the shroud on the top, or perhaps you took it off for the photo? I doubt if you have ethanol in Kenya. My wife is from Kenya and I have traveled there several times.

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Phototone,
Gud to hear you have a Kenyan wife; ask her one day to cook you Ugali (or chapo) and I promise you won't forget that delicacy for years to come!
I had removed the shroud so I could take the picture well. We don't have ethanol in Kenya (last time I came across it was in a lab a decade back); I am using petrol/gasoline mixed with oil in a ratio of 32:1.

Thanks guyz for your help. Hopefully, the Boy will be up and running come next week!!!

rev20 said:

...
Concerning these types of mowers in Kenya, the mech had no idea where they came from. He also noted that there are very few around left.
BTW, you seem interested in Kenya, are you from here yourself?


...

Click to expand...

No, I'm from the USA but I'm just very curious about how a LB got to Africa. This is the first I've heard of one outside of the US or Canada.

Please let us know how this repair works out.

My Kenyan wife cooks Ugahli quite frequently. This (for those who don't know), is a thick corn meal mush made from white corn meal and water, cooked until thick enough to be held in the hand. It is a staple, and is served with meat and vegetable side dishes, all to be eaten by fingers.

actually i was watching a episode of dr who, the new one and they were in the uk filming and pretty sure i saw one in na background shot, so who knows.

:thumbsup: im gonna have to look for a recipe for that chow

Hi:

Your mower is one of my all time favourite mowere! I am still using a 5239 for all of my hand trimming.

I think that you may be over priming te engine when it is cold thus the starting difficulties. Mine take 3 or 4 primes when cold and none when warmed from running.

Glad you got the problem solved. Take good care of that machine and it will last you a very long time!

Stay well,

Franchi

Finally got the seal, rings and bearings replaced. After fixing it, the boy started up without any troubles and I managed to mow a good chunk. The only problem I seem to be having at the moment is that the mower has trouble starting when hot. For example, say I am mowing an area with tall grass and it sputters and dies. When I try to restart it, it completely gives up on me and I have to wait until it's cold to start it again.
I have no idea why it's behaving like this. Has someone experienced this before?
Also, it's becoming really hot (like you can't place your hands there) especially underneath the flywheel (either the carb or the thing adjacent to it).
Almost forgot: I should also add that the flywheel seems to brush against the magneto coil on one side.