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Hi all. Decided to grease the spindles on my '99 Murray with the 17hp BS Twin II. Had the front end raised with the Mojack. After I put it back on the ground the mower refuses to run. It will start but not build speed and seems to choke down and quit. Saw puffs of black smoke out the exhaust.

Tried to start with the choke and no choke, doesn't seem to make any difference. Sprayed a little carb cleaner down the carb throat and it briefly seemed like it was going to spin up but quit again. Why would all of a sudden seem to be not getting gas after running perfect beforehand?

I pushed it back into the shed and put the battery tender on it overnight. I might try changing plugs and fuel filter on it today if I don't hear anything otherwise. Thanks for any advice.

Sounds like you may have had a little water/trash fuel gathered in the fuel tank. Most of the time this little bit of water/trash fuel does not move around. When you jacked it up, the water moved toward the tank fuel outlet.

A little trash from an open fuel can also be the issue. Fuel cans are seldom checked or cleaned.

I recommend you drain all the fuel out that you can, then blow the tank dry if possible, or let the machine sit in the sun for a couple of days with the fuel cap off.

Humidity in the air collects in fuel tanks over time (years) This humidity eventually forms droplets. It happens to gas powered machines and gas cans that are left sitting for long period of time. It is best to keep you fuel tank full and that will minimize the problem.

When you refill the tank, only use new fuel from the gas station. Non-Ethanol is best if you can get it. If not use the mid-grade selection I do not recommend the lowest price budget fuel because problems will keep happening.

Thanks for the reply. I kinda ruled out bad gas since the last gas I put in was only about 2 mos max old and I use stabilizer in my over winter fuel since the equipment is run less. I always buy 87 non ethanol for my small engines also, have for years. And I had run the tank on the Murray completely empty not that long ago.

That being said I'm certainly no expert in the field. So, I've drained the tank, blown out all the fuel lines to the carb and will reassemble with a new filter I have on hand. I also already picked up fresh gas this morning. The mower is sitting in the sun now drying out before reassembly. I'll let everyone know if this works.

Cleaned tank, (it looked spotless beforehand), blew out fuel lines to carb, new fuel filter, fresh gas. Still won't run. Got a pair of new plugs and it tried to run a little better but still no go.

Something must have gotten upset inside the carb when I had the nose up in the air? It didn't have much gas in the tank when I raised the front end, could a big air bubble have gotten in the line somehow. I did not try to restart it until it was flat on the ground again. The plugs were dry when I removed them. Looking down the throat of the carb, it looked super clean. It's a replacement carb I installed 8 yrs ago,

Is your engine the opposed twin cylinder or the V-twin? I just want to clarify.

The opposed twin cylinder version had a pulse pump diaphragm built onto them that would fail without warning like this.

The diaphragm is pretty simple to replace.

My numbers are 42E707, 2631E1, 9903155A if that helps identify. I know it as a Twin II.

Those number show to be an opposed V-twin. The trouble is likely in the carburetor fuel pump, or your fuel filter shifted debris inside when you lifted it up in the front and it created a blockage.

Here is a Parts tree link:

Auto Doc's said:

Those number show to be an opposed V-twin. The trouble is likely in the carburetor fuel pump, or your fuel filter shifted debris inside when you lifted it up in the front and it created a blockage.

Here is a Parts tree link:

PartsTree - Home of OEM Parts for Outdoor Power Equipment

Parts lookup and repair parts diagrams for outdoor equipment like Toro mowers, Cub Cadet tractors, Husqvarna chainsaws, Echo trimmers, Briggs engines, etc.

www.partstree.com

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Pull dipstick & check for gas in oil sump.

Thanks for the info! I ordered a fuel pump kit, I've got the 4 screw model carb. I'll report back the results.

Mark, I pulled the dipstick, no problem there. Thanks!

Last week I had a similar problem - on a much smaller scale. I pulled out two mowers from winter storage to clean them and get them started. The first was an older Toro with the Suzuki 2-stk. It's always been a hard starter. This year I put about a quart of 'fuel' (engineered 50:1) in it and primed the hell out of it. It started on the first pull. It has never done that before. I think all the priming had more to do with the fast start then did the fuel.

The second mower was a small, light, aluminum deck Weedeater with a Tecumseh engine. I put 4-stk fuel into it. Usually it starts very well. But I think I gave it too much prime (after my Toro experience). Pull, pull, pull... Nothing. Either in the intake. PPP, nothing. Either in the plug hole. PPP, nothing. So i was pulling the bowl off of the carb and fuel overflowed the bowl. I parked it and came out the next day figuring I'd have to pull the carb. But being old enough to remember tinkering on cars, I first tapped the bowl with a screw driver. First pull. I had flooded it. I let it run for a while and it's ready for summer.

I'll continue to use 'fuel' in both mowers for the summer. They each have a specific use. My normal walk behind (6.5hp Kawi) and a 12hp Snapper get premium non-oxy gasoline as they get much more use. I do use fuel in my chainsaw and pressure washer. It's wonderful stuff.

Morel - you can flood an engine beyond life!

Buying pre-mix 'fuel' is like buying water. Why? Why pay $20/gallon when you can buy ethanol-free gas for $4/gallon and mix in a $2 bottle of 2-cycle oil? I saw a 2-gallon can of a popular brand of pre-mix gas at Walmart a few days ago for almost $40. That would last me about a week as much as I go through. Not even close to practical. In my opinion, of course.

Hi farmerdave1954,

If a person uses 2-strokes a lot, then it makes sense to mix your own oil and fuel.

Hi farmerdave1954,

If a person uses 2-strokes a lot, then it makes sense to mix your own oil and fuel.

Why all this concern over non-alcohol fuel. I have been using 10% alcohol fuel ever since it came out. Never had a problem. The alcohol will absorb any moisture or water and solves that problem. I mean gas line anti-freeze is alcohol. The Briggs and Stratton manual says 10% alcohol gasoline is acceptable. However, I couldn't use 91 octane 10% alcohol gasoline in my airplane because the alcohol dissolved the carb gaskets and caused leaks. But I did use 91 octane non-alcohol auto gasoline in my airplane and it ran fine. I did have to get an FAA approved Supplemental Type Certificate to use the auto gasoline legally, but the modification consisted of two decals near the wing tank gas caps. The Lycoming -0320- E2D was designed for 80-87 octane aviation gasoline that is no longer available. To test gasoline for 10% alcohol get a small glass bottle with a lid. Mark the jar in 10% increments. Put in water up to the 10% line and fill with the gasoline to 100%. Put on the cap and shake vigorously. Let the jar stand for 5 minutes or so until it settles. If you just get the 10% water back, the gas has no alcohol, but if the water line is up to 20%, you had 10% alcohol gasoline. Just a little chemistry test.

Hello rhkraft.

Ethanol absorbs moisture from the humidity in the air, and that moisture never goes away, it collects over time and increases. Aside from that the actual gasoline breaks down and oxidizes with time. Hot weather just speeds up the process.

Many carburetors on small engine equipment are still made of (low grade/low Nickle) aluminum and usually have steel fuel bowls. Aluminum is a self- sacrificial metal that breaks down and develops a white powdered coating oxidation when exposed to moisture. Naturally the steel bowl breaks down as well.

Small engine equipment usually has a very rough life because it is left sitting with fuel in it for very long periods of time.

There is no real issue using the E-10 or E-15 fuels as long as it is frequently used and not left sitting. It is developed for high turnover.

Non-Ethanol fuel just extends the amount of time the fuel can sit unused; it simply breaks down much slower over time.

No one can truly predict when they will last use their small engine equipment, but it will be much more reliable if they empty the tanks and run them dry when the cold weather finally comes. The recovered fuel can simply be put to good use in their daily driver.

How many people will actually do that though? Not very many, so the cycle of neglect continues season after season.

Of course, the manufacturers who make the small engine equipment will not tell customers about this because it will threaten their future sales.

Any machine, regardless of brand becomes a throw away if it is taken for granted and neglected. Some just suffer more abuse than others.

I do use 'manufactured' fuel in small engines that get little use. My Toro/Suzuki 2-stk gets it as I use in only for a small portion of my yard. Pressure washer, small trim mower, chains saw. I don't use the chain saw like I did when I was younger. A friend recently bought a $1700 Stihl. He said that Stihl and some other manufacturers extend their warranty by 2 years if you use 'fuel'. They, Stihl, must think it's good for small engines.

Expensive? Relatively - but I bet I spend less that $20/year to use it.

g-man57 said:

I do use 'manufactured' fuel in small engines that get little use. My Toro/Suzuki 2-stk gets it as I use in only for a small portion of my yard. Pressure washer, small trim mower, chains saw. I don't use the chain saw like I did when I was younger. A friend recently bought a $1700 Stihl. He said that Stihl and some other manufacturers extend their warranty by 2 years if you use 'fuel'. They, Stihl, must think it's good for small engines.

Expensive? Relatively - but I bet I spend less that $20/year to use it.

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Good pre-mix oil such as Stihl synthetic (gray bottle) is more like $5 bucks per 2.5 gallon bottle, not $2 dollars.

Ethanol is hygroscipc (meaning it attracts water). All I run is 10% ethanol in all my equipment. Small engines will not tolerate 15% ethanol. Most people think ethanol is evil and continues to be a hot topic of debate. Funny how I never experience fuel related issues running it and am a small engine repair shop owner/operator.

Engineered or canned pre-mix 2-stroke fuel is not only expensive, it is not ideal for engines. See YouTube videos and forums for details.

Tiger Small Engine said:

Good pre-mix oil such as Stihl synthetic (gray bottle) is more like $5 bucks per 2.5 gallon bottle, not $2 dollars.

Ethanol is hygroscipc (meaning it attracts water). All I run is 10% ethanol in all my equipment. Small engines will not tolerate 15% ethanol. Most people think ethanol is evil and continues to be a hot topic of debate. Funny how I never experience fuel related issues running it and am a small engine repair shop owner/operator.

Engineered or canned pre-mix 2-stroke fuel is not only expensive, it is not ideal for engines. See YouTube videos and forums for details.

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So synthetic fuel is 'not ideal for engines'. But synthetic pre-mix oil is? Did I get that right? Hmmm.

As for 10% ethanol, in a small car (I've had Civics and Corollas), I got 10% less mileage with E10 than gasoline. My math tells me that I then burn just as much dyno with E10 as with gas. I have yet to find an authentic, close loop, test of e10 vs. gasoline. I wrote to Iowa State - a noted Land Grant school to see if they had run such a test. No reply. The silence was telling.

Update on repairs. I changed the entire fuel pump section with one I had on a parts carburetor and the fuel still isn't flowing. Before I open the carburetor and possibly open a new can of worms, haha, I want to change all my fuel line and the filter again to insure that isn't the problem. Does this mower use 1/4 inch or 5/16 inch line? Right now it has 5/16 line on it?

While working on the fuel problem, I took the engine side covers off and cleaned the finned cylinder areas. Both side covers had silver sections attached that curved under the cylinders. They were both loaded with dirt and grease, I'm sure that blocks air flow and cooling to the cylinders. I got them cleaned up good and reinstalled. What is the purpose of these shrouds?

Back to the Murray problem, I did a compression test today. Cylinder 1(left) 0 psi, cyl. 2(right) 110 psi. Suggestions?

Hi motormike,

The reason for the air shrouds is to concentrate air around and through the cooling fins of the cylinder(s). The flywheel air fins and top cover are what force the air past the cylinder(s). Without them they would allow overheating and eventually the motor will become physically damaged internally.

I tried to reply to the no compression issue on one cylinder earlier, but my reply disappeared somewhere.

Anyway, the engine likely bent a pushrod due to an overheat or lack of proper adjustment. No compression means an intake valve is not opening on that cylinder.

Be aware that valve guides will also slip up out of place in the head and the rocker will collide with the valve retainer and spring assembly. That will also bend a pushrod.

If the guide has moved up out of the head, the head should be replaced. Driving the valve guide back down will not fix the real problem. The machined press-fit tolerance that holds the guide in place has been compromised.

Auto Doc, this is a flat head engine, it has "pushrods?"

I'm going to pull the head cover and look for a blown head gasket. Clean up the carbon, put a straight edge across block and cover.

There are 9 head bolts, I assume they're reusable? Do they usually come out without issue? Then I'm thinking I can turn over engine with the starter and watch the valves to see if there's any issue with their operation?

motomike said:

Decided to grease the spindles on my '99 Murray with the 17hp BS Twin

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Well due for maintenance. Check your engine manual for proper instruction.

1.De-carbon the cylinders.
2.Lap some valves.
3.Check valve clearance.
4. Pull fuel line AT the carb inlet. Drain into a glass jar. Watch for a solid fuel flow. Look for water in the bottom of the jar.
5.Make sure both cylinders are contributing.
6.Clean cooling fins.

motomike said:

Cleaned tank,

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Riiiiight.....

motomike said:

blew out fuel lines to carb

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Fuel lines from 1999 are due for replacement. Lines actually fail internally where you can't see anything.

motomike said:

new fuel filter, fresh gas. Still won't run. Got a pair of new plugs and it tried to run a little better but still no go.

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Need to verify good flow of fuel into carb. Also pull the oil stick and smell for fuel as another person suggested. Crack open the fuel tank cap and see what you get.

motomike said:

Looking down the throat of the carb, it looked super clean. It's a replacement carb I installed 8 yrs ago,

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An 8 year old carb probably 12 years old is due for a cleaning. Think you could have a ton of trash in the tank outlet, that you can't see.

motomike said:

The plugs were dry when I removed them

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What do you think this means? Not getting enough........

farmerdave1954 said:

Buying pre-mix 'fuel' is like buying water. Why? Why pay $20/gallon when you can buy ethanol-free gas for $4/gallon and mix in a $2 bottle of 2-cycle oil? I saw a 2-gallon can of a popular brand of pre-mix gas at Walmart a few days ago for almost $40. That would last me about a week as much as I go through. Not even close to practical. In my opinion, of course.

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Chickanic I think it was found bad fuel in those premixed cans that cost a fortune. Think she said don't buy that junk. It was stale and full of water.

Also think it was Taryl who found out alcohol doesn't absorb water and pass out of the engine via burning. Best to drain any suspect fuel and pour in fresh E-0 gas.

motomike said:

Back to the Murray problem, I did a compression test today. Cylinder 1(left) 0 psi, cyl. 2(right) 110 psi. Suggestions?

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1.Are the valves closing proper?
2.Do the valves seal proper?
3.Your test equipment working proper? Possible bad O-ring on the hose. Hose not tight enough?
4.Overheated and valve guide move from proper resting location?

motomike said:

Auto Doc, this is a flat head engine, it has "pushrods?"

I'm going to pull the head cover and look for a blown head gasket. Clean up the carbon, put a straight edge across block and cover.

There are 9 head bolts, I assume they're reusable? Do they usually come out without issue? Then I'm thinking I can turn over engine with the starter and watch the valves to see if there's any issue with their operation?

Click to expand...

Hello motormike,

I apologize, I lost track of out earlier conversation, and this site has delay issues that creates frustration and confusion. Being an opposed twin engine, pull the heads and watch the valve and piston movement to make sure they are working.

It been a few years since I have worked on those on a regular basis, but they were long lasting reliable engines.

The head bolts are reuseable but keep them in order of location. (A cardboard template works well for this).

It would not hurt to actually break them free by trying to tighten (tweak) them very slightly before removal. This usually eliminates rust frozen bolt thread problems.

I think I would see if the piston is moving up and down