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NITRO-BTU · Jan 22, 2009, 01:40 PM

Hello People, I would like to know how I can INCREASE the FULL- THROTTLE RPM. Setting. My 5HP. Briggs snow blower seems to strain with removing heavy snow... 6 inches or more. When I over-ride the governor momentarly [go to wot], I noticed that the governor control holds the engine back to apx. 1/2 throttle. I believe there may be a weak spring, or something that can be adjusted. Please, advise and provide pics, Thank-You, Nitro-btu.

crigby · Jan 24, 2009, 06:05 PM

Hi,
If it is a Briggs, then it is right behind the governor plate below the gas tank

KISS · Jan 24, 2009, 07:57 PM

Make sure that whatever the governor linkage attaches to on the carb is totally free. Use carb cleaner.

crigby · Jan 25, 2009, 11:56 AM

Hi,
Beneath the fuel tank and behind the bottom bracket that fastens the tank to the lower block is kindof "U" shaped piece that one end of the governor spring attaches to. With the control at WOT the spring should be almost vertical and the aforementioned piece should be at the bottom. Taking some appropriate tool and bending that piece downward, so as to put more tension on the spring will increase the speed.
Peace,
Clarke

NITRO-BTU · Jan 26, 2009, 05:53 AM

Originally Posted by crigby

Hi,
Beneath the fuel tank and behind the bottom bracket that fastens the tank to the lower block is kindof "U" shaped piece that one end of the governor spring attaches to. With the control at WOT the spring should be almost vertical and the aforementioned piece should be at the bottom. Taking some appropriate tool and bending that piece downward, so as to put more tension on the spring will increase the speed.
Peace,
Clarke

Thank-You, crigby. I will try the above mentioned procedure, and post the results when I get a chance. Jim.

NITRO-BTU · Jan 28, 2009, 07:06 AM

Crigby, As you said, the spring at WOT is Vertical, and at Idle almost horizontal. However, rather than bend the tab to increase tension on the spring. I believe, I can pull up another loop on the spring [making it 1 loop shorter] to increase the tension. What do you think of that? Jim.

crigby · Jan 28, 2009, 09:46 AM

Hi,
You can but you stand also the chance of modifying the springs tension. With the Model and Type nos. off the engine you can look up a spring with more tension at the Briggs website; they will be item #209 and will reference the top-no-load speed it is rated at.
Peace,
Clarke

NITRO-BTU · Jan 30, 2009, 06:21 AM

Crigby, I bent the u shaped tab down to increase spring tension. What I found by doing this, actually caused the engine to run lean near WOT. So lean that it would not run @ what, and the exhaust was cherry red.
The only way this might work is to change the brass main jet to a Larger size. Will... the fuel pump be able to pump enough gas to richen it @ WOT, and when at idle it may be to rich to run, or[idle] ? I was only trying to Maximize the engine's potential, but it appears that has already been done through Engineering.
What do you think of my Discovery? Jim.

crigby · Jan 30, 2009, 09:36 AM

Hi,
This is not how the engines are normally designed. Increasing the speed should not be a mixture-affected event.
Carbs are designed with four basic circuit characteristics; first is the pilot circuit which does the work to 1/8 throttle, second is the first intermediary circuit that does the job from 1/8 to 1/4 throttle, third is the second intermediary circuit which does the job to 3/4 throttle where the main jet takes over. This is a simplified picture of the engineering process of the carb. Not all circuits must be discrete, obvious or independent. There is always a transitional overlap of one to another in a well-performing engine.
The jist of that is a larger main will not be noticed by a pilot circuit.
Got any numbers off the engine? Manuals(service) are to find online, but I have read them for thirty-odd years already.
Peace,
Clarke

NITRO-BTU · Jan 30, 2009, 10:50 AM

HERE ARE THE NUMBERS... 130292... 1061 02... 80090806... I already know about the carb circuits, ran engine dyno for Ford's. This carb has only one needle valve, and it meters gas flow through the main jet. So, I believe in this case that the idle will be affected by a larger jet. Turning this needle from its normal 1 1/2 turns out setting has effected the lean/rich mixture through all RPM. Ranges.
Secondly, I believe there is a small air leak somewhere in the carb, because the engine wiil not start COLD with the choke on. Rather, I have to prime it through the choke... then choke it to start. After it warms up... it will start without a prime. I do believe this condition has something to do with the Lean A/F Condition Near WOT. Also, the carb has been soaked/cleaned, and has a new fuel pump diaphram with spring, and cap. Please, evulate this additional info... and see if you can pin-point the problem.
Thanks again, Jim.

crigby · Jan 30, 2009, 11:30 AM

Hi,
I agree with your assessment of the lean running condition. I agree with the air leak conclusion, also.
The 299060 jet assembly is actually two jets in one assembly(one fixed and one adjusable) mating into one unit. The adjustable one controls most characteristics of mixture.
Just a question, when you replaced the diaphragm, where did you install the cap? It prevents the end of the spring from abrading a hole through the diaphragm(an air leak possibility.)
Barring that, try cranking the engine, warming it up and changing the mixture characteristics with some form of spray(needs to be flammable) to see at what place the engine operation changes. Could be carb cleaner, WD40, brake cleaner(flammable.) When it hits the leak, the RPMs should change as the mixture has richened.
You could be unfortunate and have a porous carb body that the cleaning revealed(rare with zinc carbs, but not unheard of) and require a replacement carb. Think I would look for a used one since your engine was made Sept. 06, 1980.
Peace,
Clarke

crigby · Jan 30, 2009, 06:09 PM

Hi,
Got to thinking about that answer, and I misspoke. You are right beside the muffler and should NOT use a flammable liquid spray to check for air leaks. They are so handy because the engine can burn them, just change running characteristics. The nonflammable sprays work, but can cause repeated needs to recrank engine. Some that will not harm the engine would be some of the sprays available to loosen rusty or stuck fasteners and some types of brake cleaners. The label will say.
Peace,
Clarke

crigby · Jan 30, 2009, 07:08 PM

Hi,
BTW. The governor spring is a 260695. I have the parts manual if you would like it emailed to you.
Peace,
Clarke

NITRO-BTU · Feb 1, 2009, 07:10 AM

Crigby, Very good point about where to put the cap with respect to the diaphram. Well I thought to protect the diaphram, it should go between the spring and diaphram, leaving the other end of the spring to butt up against the inside of the carb.
With respect to Air leaks, where would you think the most likely place could be with this type of carb ?
Yes, I would like the parts manual.. . Please E-mail it to... [email protected]

Thank-You, Jim.

KISS · Feb 1, 2009, 08:26 AM

Diaphram carb - the primer bulb

crigby · Feb 1, 2009, 08:53 AM

Hi,
Manual sent. Well, to look at it logically, there are a limited number of places that an air leak would have an effect(ie where air could enter and change the mixture of fuel and air adversely.) The carb is shaped roughly like a large cigar, but fuel does not enter the air stream until it reaches the location where that jet is. So, it would be between there and the engine block. It could leak at the pump cover(rare but I have seen them warp, or the diaphragm to accidentally get slightly folded, actually the go-kart racers used to do it on purpose - illegal, but hard to catch) or at the intake gaskets. Anywhere else but at the jet inself, there is an aluminum or fiber gasket there, would have to be in the body itself, and would mean carb replacement.
As an aside, since you say the carb was cleaned, that means the tank/carb were taken loose. It is easy to damage the governor spring when disconnecting it from the tank's throttle linkage. A practiced mechanic can loosen it without disturbing its location on the governor arm. When I was newer to the "game" that was not often the case. There are a number of holes in that arm and which one used affects the operation in some often unpredictable ways. The correct hole(s) are near the inverted "V" shaped notch in the arm. I will try to find a repair manual, though I have little success finding a Briggs(some Tecumseh and Kohler, yes) online.
Peace,
Clarke

NITRO-BTU · Feb 3, 2009, 07:12 AM

HAVE ANY OF YOU PEOPLE HEARD OF "SEAFOAM FUEL SYSTEM CLEANER"? I have read up on the stuff, but I don't know if it Actually Works. I would like some direction here. Thanks, Jim.

crigby · Feb 3, 2009, 01:40 PM

Hi,
Never tried it myself, but it is the "darling" of the motorcycle world. Originally made in the 1940's as a cleaning additive for the boating industry(hence the name) it has found favor among many mechanics who deal with engines that have sat with fuel in them for extended periods.
It seems that about 8 oz. to a tank of fuel and run that through it. Add again on fill-up and run part through, then allow to sit a couple of days to attack the remaining varnish seems to be the best recommendation any of my biking friends could give me(I gave up bikes some years ago, except the pedal variety for exercise.)
The company makes three products. It can, and is promoted for, the cleaning of injectors. There is a transmission product, also.
Peace,
Clarke

NITRO-BTU · Feb 11, 2010, 08:24 AM

HELLO THERE Crigby, It's been a year, and now I'm in the middle of another Winter Wonderland here in Mich. You might remember Some of my Questions regarding the 1980 5hp. Snow blower. Well, Increasing the governor spring tension, has made things worse, but I had to try it. Now, aside from that... ALL THE PRIOR PROBLEMS HAVE REOCCURED THIS YEAR AGAIN. The fuel last year, was Heavily treated with gumout type cleaners to Extreme... 4oz. Per. Gallon of gas. YES, It Ran Fine before putting it up for the season, and still had the same fuel into this year 2009.
Somehow the main fuel jet has another restriction, or is varnished up. I suggest, to Refresh your memory, Please go to: "WOT/Governor Control Speed," there are 2 pages.
Crigby, Please give me your take on this nightmare. Thanks, Jim.

crigby · Feb 11, 2010, 10:10 AM

Hi,
Have you tried checking the screens at the bottom of the pickup tubes? Older engines sometimes had the screen on the long one varnish over and affect the fuel mixture. About a decade before they had a problem with the long tube failing out of the body completely. Looking in through the gas cap opening would reveal that.
Peace,
Clarke