Help with throttle adjustment and linkage on an old 3HP Briggs and Stratton

hashburyfl

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  • / Help with throttle adjustment and linkage on an old 3HP Briggs and Stratton
Hey All,

I just acquired an old edger that cost a grand total of 10$. 25 hours of labor later I have it running fairly decently but I'm having an issue with the throttle.
Engine: 090212-0216-01 -- 91100103

1. I dont have a throttle lever for it but im assuming i can just find a side mounting one online that will work unless anyone knows of a better idea.
2. More importantly, the throttle cable is not increasing the throttle as it should or not at all really.
The throttle cable comes from underneath and hooks into the same adjuster the spring is connected too. The spring hooks into the air link vane, and that hooks into the blade governor.
As far as I can tell the governor is working correctly as it appears to provide resistance on the spring.
I thought the spring might be bad but it "seemed" ok. I went and increased the tension on the spring (by making it shorter) and this enabled me to get maybe an 1/8th of the throttle to move.

I just want to have a reliable way to throttle up and throttle down.

Does anyone have any ideas on what i could do or maybe know something about this engine I could be missing.


Thanks for any help!

Pics are before the work was done (just in case someone noticed all the rust in the tank)
 

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slomo

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  • / Help with throttle adjustment and linkage on an old 3HP Briggs and Stratton
Just bought 2 McLane edgers with the Briggs 3.5hp engines. I have a bunch of tips for you.

1.CLEAN the cylinder block cooling fins. All that dirt and oil needs to come off NOW. If you neglect this you are asking for engine damage. This is in your engine manual as a yearly maintenance item.

2. The bracket and screw plus the small spring need to be added. It helps hold the throttle open. I would say this is a must. You can find this carb on ebay for 20 bucks. The spring alone from Briggs is 10 bucks. Might as well get the entire Chinese carb as the Briggs parts are no longer made.

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3.Your throttle linkage is bent wrong. Should connect to the lever plate on top and have a slight bend up where yours bends to the left heading towards the air vane. Not a big deal on yours. A new linkage is bent differently.

3.jpg
 

slomo

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  • / Help with throttle adjustment and linkage on an old 3HP Briggs and Stratton
I have one that has a throttle cable and the throttle/choke control panel like yours.

Here's an important tip. Don't get into the habit of trying to idle down the engine. These are splash lubed and air cooled. Briggs states run at full 3600rpm for max engine durability. On the cooling, idling down drastically decreases cooling which can lead to engine damage. Talking valve seats jumping out of the block and valve guides moving around ect....

Only time I move the throttle cable is to kill the engine. When I use the edger again, move the throttle lever to where I get 3600rpm and pull the rope. Leave it alone.

Also when adjusting throttle linkages and springs, you need a tachometer to set rpm's. You will be surprised at when you think its running too slow how fast it really is running.

slomo
 

slomo

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  • / Help with throttle adjustment and linkage on an old 3HP Briggs and Stratton
Here is the ebay link for the Chinese carb.

This has the newer model additional throttle spring and bracket I was talking about.


slomo
 

slomo

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  • / Help with throttle adjustment and linkage on an old 3HP Briggs and Stratton
Noticed yours has 2 carb to engine gaskets on it. Looks like yours already has a Chinese carburetor on it. These ebay carbs use much thinner gaskets than the OEM Briggs. OEM uses 1/8" thick gaskets. Ebay carbs come with 1/16" gaskets.

slomo
 

hashburyfl

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  • / Help with throttle adjustment and linkage on an old 3HP Briggs and Stratton
Slomo,
Thanks for all of the above its super helpful.
I hit the fins with air but I will put on some degreaser and take a wire brush to them as they are pretty thick.

I have a few of the Chinese small engine tachs so I will throw one of those on to get an idea of where the rpm's are. I'm not sure how reliable they are though.

I'll also order the additional Chinese carb as when I cleaned the one it has now I used a liquid gasket maker because the gaskets ripped when taking it apart. For 20$ its a lot cheaper then ordering oem parts separately.

I really appreciate the help.
 

hashburyfl

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  • / Help with throttle adjustment and linkage on an old 3HP Briggs and Stratton
One more question...
Do you know how much oil this engine holds? Mine just has the caps and I dont see anything for a fill line.
 

hashburyfl

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  • / Help with throttle adjustment and linkage on an old 3HP Briggs and Stratton
And also.
One more question...
Do you know how much oil this engine holds? Mine just has the caps and I dont see anything for a fill line.
I fit around 18oz or so in it. Seems to be pretty close to what it should be.
 

slomo

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  • / Help with throttle adjustment and linkage on an old 3HP Briggs and Stratton
One more question...
Do you know how much oil this engine holds? Mine just has the caps and I dont see anything for a fill line.
I don't get involved with ounces at all. Why because you can tip or drain one and never get the full 18 or 20 ounces back into it. Just drain and refill to EXACTLY the full mark. Don't make it any harder than that.

On these horizontal crankshaft engines you do this.

1.CLEAN all around the oil caps. Make sure no grit will be able to get into the oil. My engines have two oil caps, one on each side.

2.Drain oil oil by tipping or using a vacuum pump.
4.PNG

3.Engine on flat ground. Add SAE30 oil ONLY. I use Walmart SuperTech SAE30 SG rated oil. Has lots of ZDDP zinc in it for flat tappet cams. Fill the oil till it runs to the top of the threads on the oil cap. Basically to the point of over flowing.
 

slomo

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  • / Help with throttle adjustment and linkage on an old 3HP Briggs and Stratton
Again on the cooling fins cleaning. Make sure you clean the top of the block under the flywheel and all other areas.You'll need to remove the fan shroud cover that houses the pull start rope. Look all around the block for oil and dirt areas.

A dirty oil layer will insulated the block leading to over heating. Keep[ the revs up and oil FULL.

slomo
 
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