[NITRO-BTU]

YES, When I cleaned/soaked the carb last year, I did replace the long plastic tube with a new one. There is one strange thing that I have noticed. It appears to run out of gas at a 1/3 tank level. Which may have something to do with the longer pick up tube. I put fresh gas in it the other day, but did not happen to check the tubes. If the long tube should happen to fall out, what would happen, what are the symptoms ? WOULD THE ENGINE RUN AT ALL ?
What about the increased governor spring tension, (I bent the tab) would that prevent the throttle from responding properly under load conditions? Thanks Again, Jim.

[crigby]

Hi,
If the tube falls out, the engine will run for 1/4 tank or less by the suction and splashing action, but the ones that fall out are brass. They had a replaceable end. Never seen a plastic one fall out.
Some plastic pickup tubes have a sort of check valve near the bottom. It will be visible through the side of the tube at the bottom. Will look like a sleeve with a seam rather than a valve.
As cheap as diaphragms are, I never fail to replace them often if any other service is done.
I have never seen a larger jet for that particular carb, but it is possible that some go-carting site offers them. Most of those engines other than the outlaw class have to comply with some very strict requirements and restrictions. Most will have far newer versions of all parts because of the lifespan expectation being exceedingly short.
Peace,
Clarke

[NITRO-BTU]

Clarke, I don't know about the engine running for a 1/4 tank of fuel due to suction, and splashing action.. . That seems a bit of a STREECCH ! If that were the case, then that fuel pump diaphram is "Golden."
What do you think about drilling out the main jet a "few thousandths larger?" Also, what about the governor spring tension? Thanks, Jim.

[crigby]

Hi,
Saw the 1/4 tank thing on Sensation roll-around blowers in the 1980's when the brass tubes would fall out.
The tool I have used on jets was the tip cleaning tool for oxy-acetylene torches to clean them. It is a bunch of almost little rod files of graduated sizes.
I would get the carb to work before worrying about the governor too much. Unless it is way off, it is the secondary issue.
Peace,
Clarke

[NITRO-BTU]

Clarke, I need to know Exactly what problems low cylinder compression can cause. For Example, figuring everything else is working properly. (1) With the engine hot, or cold... it must be primed through carb choke, or through spark plug hole, in order to Start it. (2) When running hot, or cold Never really know what to expect... sometimes it runs best with choke closed, and other times it Must be just Cracked open a 1/8." VERY SPORATIC / UNPREDICTABLE ENGINE PERFORMANCE. (3) Then just when it stabilizes, and plows through the heavy snow... 5 minutes. Later it acts as if it's Running out of Gas, and Dies. (4) It will not start after this until it cools down. I have eliminated the ign. Coil, because if the engine is not under load, most of the time, it will run until out of gas.
Last year I put some carb cleaner in the tank, and ran it at fast idle for two hrs. with no problem.
Please, take your time, and evulate All of the above problem info. Then through the numbers, Try and make Sense of this NIGHTMARE.
Again - Many Thanks, Jim.

[KISS]

1) Means fuel related
2) Fuel related
3) Fuel related - probably flooding (remove spark plug and inspect for wetness)
4) Fuel related - Too much gas is vaporizing because of a hot engine - again check plug as in#3

If you suspect compression, do a compression test with and without some oil in the cylinder.

Do we have any sort of smoke colors like white or blue at any point?

[NITRO-BTU]

"CALLING - ALL ENGINEERS," I agree it has to do with fuel, but I need Some SPECIFICS ! What part of the carb is Faulty to cause this sporatic behavior. EXAMPLE: WHILE ITS RUNNING WITH POWER... its plowing the snow, then out of the Clear Blue... IT FLOODS? "WHY?" What Change takes place to Cause this Flooding ? Does it have anything to do with the Governor ?
Also, I haven't noticed any smoke colors - blue, or white, but there have been Sparks on occasion with Backfiring.
COME ON CLARKE - Take a shot at this. Thanks, Jim.

[KISS]

Four things in particular come to mind:

One is governor related. Make SURE that the gizmo on the carb that controls the throttle is totally free. The governor has to be able to move it with little effort. Clean with carb cleaner if it isn't.

The second is a sticking fuel valve.

The third is something like a piece of rust in the fuel line, but that occurs if the tank is metal.

The fourth is a blocked gas tank vent on the cap.

Fifth is a plugged internal port. I hated that in a 1982 carbed Totota. About 120 parts to rebuild it and drill out some caps. Carb worked, but I had to take off the top and tighen the fuel valve assembly.


An aside.

You could check the compression when the engine is cold and hot.

[NITRO-BTU]

On pg.#1 / post #10 are the engine numbers. Numbers 2, and 3 Don't apply. The Governor - I believe by resetting the bent tab to its original position, that it's OK. Throttle does move very freely with No binding. Last year, I replaced the gas cap.
My best guess is that there is either a massive internal restriction Causing a Lean Fuel condition, or massive air leak in the carb.
Why else, with a full-choked engine would it run with power to plow snow, If there Wasn't a Massive internal Air Leak in the carb ?
HOWEVER, The flip-side of this Nightmare... Having an internal restriction within the carb body, Would Definitely cause a lean fuel condition ! EITHER OF THE ABOVE Scenarios would bring about the same effect. Lastly, when fully hot, the engine runs with the choke Cracked Open 1/8" for Maximum Power, or 7/8" CLOSED !

Again - Calling on ALL Engineers. Thanks, Jim.

[NITRO-BTU]

" IT APPEARS that the VERY BEST are stumped by this SPORATIC Engine Non-performance !"

[crigby]

Hi,
Well you said that it could run correctly with no load? Engines with a marginal ignition can do that. I have run three tanks of fuel through machines and done other tests without problems when not loaded. I have even had to seal off the discharge of a rider deck, engaged it and used a garden hose delivering a stream of water under it to load it enough to produce a failure.
As far as compression goes, the manual says to spin the flywheel backwards by hand toward compression and look for a minimum 90 degree bounce back.
I have found manuals online finally, though I cannot say they will remain available. See:
http://www.mymowerparts.com/pdf/Brig...20STRATTON.pdf
Peace,
Clarke

[NITRO-BTU]

Clarke, I Will at this point... buy a compression tester, to find out for sure. I would use the roll-back 90 deg. Method, but the drive end is enclosed. However, I can tell you that when cold, the resistance to compression when pulling the starter cord slowly is weak. Normally, you can easily feel the resistance when approaching TDC on an engine with Good compression.
Would you happen to know what the compression should be on a good reading ? How do I go about taking this reading ? FOR Example: Should I pull fast, and take each reading on the gauge for 10 pulls, then average, and then 10 slow pulls ? What's the Procedure ?
Thanks, Jim.

[KISS]

Modern engines have a "compression release" system. In the Briggs engine moving the flywheel backwards disables that system.

If anything, your looking at compression with a cold and hot engine. And compression with and without oil injected.

Pulling in the correct direction will get you nowhere because of the "compression release system".

Take the blower housing off and spin the flywheel manually, backwards. Fast doesn't mean anything either.

[KISS]

Think about how a compression gage works. It may consist of something tat threads into the spark plug hole and sometimes it contains two different sized threads and seald with an "O" ring.

There is a check valve on the gage, so it registers the highes compression and there is a release port. Usually a schrader valve that you push with your finger before removing the contraption.

It doesn't matter how fast it turns. The same amount of air gets compressed regardless. The gage registers the maximum PSI.

[crigby]

Hi,
I said to try the "bounce-back" technique not only because it is in the manual, but because of the reason it is in the manual. Most current engines use an ACR which disengages at running speed. Older Briggs engines have "Easy Spin" systems which mean the exhaust valve opens slightly on the compression stroke. It becomes mostly moot at higher RPMs, but never stops no matter the speed. My suggestion would be to pull the carb, head, breather and valve springs. Check the valve clearance; sounds as if you have too little. This will affect the pulse charge that affects the fuel pump on the carb. I will attach the link to the chart, yours is the 130000 and notice no compression reading is given! See:
http://www.mymowerparts.com/pdf/Brig...S%20270962.pdf
Peace,
Clarke

[NITRO-BTU]

Clarke, I really do appreciate all the technical stuff, and am moved by it. However, there must be an Overall Miminum cylinder compression PSI. for this engine, whatever it happens to be. Will the engine Run with less than 60 psi ?
I believe the valves need lapping, as well as an adjustment.
Again, Please give me your take on this.
Thanks, Jim.

[KISS]

I found this online: Briggs and Stratton Small Engine Fault Diagnosis

It offers a quick "compression check" without a gage.

[NITRO-BTU]

Reading through the rich, and lean probable causes, I noted that a defective/bad fuel pump diaphram may cause a rich, or possible a flooding condition. To the contrary, if there were a hole, and, or a tear in it, Wouldn't it simply "Fail to pump fuel?"
Also, noted with the "lack of sufficient compression," no fuel can be drawn in for combustion.
WHY are there No compression specs. For these engines ?
Give me your Best guess, as to what the compression should be for this engine, from min. to max.
Thanks, Jim.

[crigby]

Hi,
A "healthy" Easy Spin engine cranked at about 900 RPM should have about 65-90 psi. That RPM generally requires an electric starter since recoil/hand starting only produces 600-650 RPM at the best.
Briggs says it is not reliable even then.
A fuel pump with a pin hole will usually just not pump well. An engine down on compression will work the breather less because it will not have to compensate for the amount of ring blow-by that a healthy engine produces. Less blow-by, less pressure differentials that exist in the crankcase to operate the pump.
Peace,
Clarke

[KISS]

I'll tell you two fuel related true stories:

1. I was 15 YO and got my first car. Could not drive it, but it was wrecked when I got it. $25 for the car and it was mine. It had the darndest time working at full throttle. Found a slit in a small piece of fuel line at the tank facing UP. Pain to find. Eventually when I was all done, got 18 MPG on a 6 cyl carbed Ford with no emission controls. Added electronic ignition, ported the intake manifold and had the heads machined and rebuilt the carb at 15 YO. That was my second car carb. Rebuild.

My father had a car that would not go up this VERY STEEP HILL. I mean steep. Must be a 45 deg angle. Car would stall. We had to go around the hill. No real performance issues EXCEPT it could not go up STEEP hills. Fuel pressure turned out to be low and it was dx'ed as a bad fuel pump. The pump was taken apart. I loved to do that to just about anything. I found a check valve that popped out of a socket.

One other fuel pump story. I was driving many miles away and the car just died. It was the fuel pump. I had tools in the car. There was one stupid trick necessary to put the fuel pump on. Grease the actuating rod so it would not slip out of the engine. Ingeneous.


Maybe a defective fuel pump fits:

No power at high loads.
Always having to choke (means more fuel)
When hot a small amount of fuel will vaporize.

Did you ever check the plug for wetness after just cranking and no priming?