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Briggs and Straton 17hp twin ii flathead


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06-24-15, 08:10 AM   #1  
Briggs and Straton 17hp twin ii flathead

My Briggs and Stratton 17hp twin ii flathead won't crank.
Model 42A707

I've replaced the starter and battery.

Compression seams to be too high. However if I remove both (new) spark plugs it cranks like crazy.

I removed the heads on both cylinders (piston, rings, cylinders and valves all Good) with each piston at tdc the valves (both input and output) are firmly closed.

I can't figure out how to adjust the rockers they seam to be inside the block and unattainable.
I can access the valve springs, but there is no adjustments there.

Any suggestions would be extremely appreciated.


Last edited by Marvin Martian; 06-24-15 at 08:43 AM.
 
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06-24-15, 09:54 AM   #2  
You'll need a good strong battery, not the $30 special to reliably crank that engine. Over 400 cranking amps.

The cables need to have good clean connections to the battery, frame, solenoid, and starter. If there is gas or oil in the cylinders, it won't be able to crank over past the compression.

The valves don't have adjustments on this engine and are not contributing to the problem.


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06-24-15, 11:55 AM   #3  
Thanks' Cheese

But even when I bypass everything by using a strong booster pack to the block and pos. on the starter it will only crank with no plugs. I even tried boosting from my car with the car engine running.

When I pulled the heads off there was no sign of oil or gas in the cylinders.

I even did an oil change and there was no sign of gas in the old oil.

to say the least I'm confused?


Last edited by Marvin Martian; 06-24-15 at 12:17 PM.
 
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06-24-15, 07:26 PM   #4  
What kind of starter did you install? An original one from Briggs or a chinese clone? Do you have your old starter?


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06-25-15, 03:37 AM   #5  
Thank again Cheese

I traded in the old starter at a specialty starter/alternator shop, I know they know there stuff, I've used them many times.

But no I don't know if it is original or a knockoff.

 
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06-25-15, 04:16 PM   #6  
If it won't turn the engine with the plugs in it and full battery power at the starter lug, then I'd say the starter isn't working properly.


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06-25-15, 05:35 PM   #7  
Thanks yet again Cheese

I went back to my starter guy and he agrees it's got to be a compression issue.

And the new starter is Briggs and Stratton and not a knockoff.

I'm Leaning more to the conclusion it's may be a compression release valve or timing issue.
However I don't know what to look for as for a compression release valve or how to adjust the timing.

I have all the tools but not the knowledge.

If anyone could give me a link to an owners manual or preferably a service manual it may help. I've tried the Briggs and Stratton web site but they don't seam to want to take credit for this engine.

CORRECTION

SHAME ON MY FACE! I did find the owners manual and Illustrated parts list on the B&S web site.

Apologies to Briggs and Stratton.

Still I don't know what to look for as for a compression release valve or how to adjust the timing.


Last edited by Marvin Martian; 06-25-15 at 06:15 PM.
 
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06-25-15, 10:49 PM   #8  
Put a compression gauge on it. That engine has no compression release mechanism. The timing is non-adjustable. The valves have no adjustments and by design, the more they wear, the less the clearance will be, meaning if it makes any difference at all in compression, it will eventually cause it to have less compression, not more. I don't see how the compression can be too high for a good starting system to crank it unless there is liquid in the cylinders.


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07-06-15, 06:35 PM   #9  
Cheese IS the man

Hi Cheese

Your advice was extremely Helpful.

After you saying my engine had no valve rockers or timing adjustments I had to step back and rethink things.

I went back to trace electrical wiring and the starter solenoid was fried. The first time I tested it, it was OK but this time dead. So for $20 I replaced it and again traced all wiring (grounds etc.). thought it may be the key ignition switch (6 pole...2 pos. terminals) but it was ok to.

It fired up!!!

I adjusted the carb, choke and throttle. She never ran so well.

I was so pleased I shut it down and started it again many times, wonderful.

And now... I'm back to square one, turn the key... click, click.

Please tell this "dummy" what have I missed?

Thanks

 
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07-07-15, 12:08 AM   #10  
Check for power on the white wire at the solenoid while you turn the key to start. If it's there, check for power at the starter. If none, there is a battery cable connection problem or the solenoid lugs got wrenched on too tight and the solenoid isn't making connection internally. If that's the case, you should be able to jump across the terminals on the solenoid with a wrench and it crank.


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07-09-15, 03:23 PM   #11  
Cheeze you realy know your stuff!!!

The white wire on my selonoid is orange (not important), power at that point with the key engaged good power. power in to selonoid O.K. power out with key engaged no good. Jumping terminals does crank the starter but I think I've sheared off the gear on it because it just spins (but not the fly wheel). I'll have to take it off to check it when I have more time.

I don't mind the $20 for another selonoid, just hope there won't be another issue killing selonoids. I'll let you know how it goes.

Once yet again thank you so mutch Cheeze.

 
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07-09-15, 09:40 PM   #12  
Ok, that wire is usually white on craftsmans but not always. The solenoid can handle more than the amperage required, but if the lugs get tightened too much, they turn a little inside and then don't make good contact.

If the gear broke, be sure to replace it with a genuine briggs part, not aftermarket, especially on that engine (it's a hard engine to crank and it's tough on starters). I've seen the aftermarket gears break in less than 5 uses.


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07-13-15, 03:53 AM   #13  
Cheeze

I hate to sound like a broken becord but... MAN YOU ARE THE' MAN!!!

She runs better then when I got it. If you like grass fed beef, bring over your cow or a bailer.

Again you are right, I did buy a genuine briggs gear but I killed the new one too. I snaped one of the bolts holding the starter under the fly wheel.

So my new question is how do I pull the fly wheel so I can tap out the bolt?

Thanks again

 
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07-13-15, 08:28 AM   #14  
Remove the large nut holding it on.. I think it's 1 5/16". Put a couple large screwdrivers under it on either side where they aren't damaging anything when you pry up. Put the nut back on until it is flush with the top of the crankshaft, then have someone pry up on the screwdrivers and hit the nut/crankhaft squarely and sharply with a heavy hammer. It should just pop off. Be careful to not damage the threads on the crankshaft or nut. A better way is to go to autozone or a parts store that rents pullers and get a puller (like a steerig wheel puller or other type that uses bolts).


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07-23-15, 03:54 PM   #15  
wow what a learning experience!

This engin never had the nut it should have since I got it, and didn't need it. The fly wheel was ceased on so tight. I tried your ideas Cheeze but no luck. I grabed the largest 3 claw puller I have and did nothing but chew up the teeth on the wheel.

I got my freind a class A auto mechanic to help me and it took us 2 hours to get it of (heat, penetrating oil and brut force).

I went on a quest to find a replacement washer and nut to hold the wheel on because I wanted to use antisease compound before I put it back together so this wouldn't happen again (heavin forbid I ever have to pull the wheel again).

Beeing in a small town the local small engin parts places couldn't help me. So I contacted a local small engin mechanic and he said he may have one.

Since I already had the tractor on the trailor I brought it with me to be shure I got what I needed. Not only did he have the nut and washer the engine was the same so I said "put a price on the whole fly wheel and washer and nut... $20.00 sold . (it took him 15 seconds to pull the fly wheel, whithout a puller)

Now again she is running better then ever, but will only start if I jump the terminals across the selonoid even with yet another new selonoid.

So my thinking is it has to be the 6 pole key switch.

Any thoughts?

 
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07-24-15, 01:09 AM   #16  
And you have power on the small wire plugged onto the bottom of the solenoid when trying to start it?

If you put neverseize on the crankshaft before putting the flywheel on, you will probably shear a flywheel key soon. There must be a dry fit between the crank and the flywheel because friction is what holds it in place. The key is only there to make sure it is in correct timing when it's placed on the crankshaft.


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07-26-15, 05:25 AM   #17  
Cheeze

Do you run around in a robe carrying francensence and mur? Because you are definitly a wise man.

Shows what an car mechanic knows about small engines, he's the one that sugested the antiseeze compound an the fly wheel.

I took your advice and pulled the wheel and removed the compound. I don't need to sheer the woodroffe key causing myself even more greif.

All my tinkering must have killed my ignition switch because no power at the small wire on the selonoid. I went direct from pos. on the batt. through a push button switch to the small post on the selonoid and she starts every time instantly with no effort at all.

Thanks again

I hope this post helps someone else.

 
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07-26-15, 09:45 PM   #18  
Glad you got it going!
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