hard 9re) starting briggs

[SUKI]

Better watch it on the homemade tools as OEM tool police are watching. My HM leak down tester was retired a couple years ago.

A couple tools I just had made would be ones they love to get a copy of. Right now I am the only with the design diagrams. Even my machinist don't have a copy.

[38racing]

I just downloaded the manuals to my laptop as I had ipl on my phone. I did the operator manual as well and browsing it I see the intake valve clearance at 4-6 thou and exhaust valve clearance as 9-11 thou. Somewhere I thought I had found both valves were supposed to be at 4-6 and that's what they are at now. If exhaust is supposed to be 9-11 then maybe my lower setting is giving me to much compression release as it's on the exhaust and I see a good bump. Maybe it's the release allowing the muffler bang. Funny, in my first post I mentioned the high valve clearances , but on both of them.
ugh update: so I find another manual showing 15 series at 4-6, 9-11 but the 20 at 4-6, 4-6. Going to look some more I guess.
another ugh update. The operator manual shows 12,15,20,21 engines (mine is 20m114) where it showed the valve clearance it says see repair manual 272147. That manual comes up as a vanguard manual with no 12,15,20, or 21 series even listed, completely different displacements.

[38racing]

so I opened manual 276781. Single cylinder OHV. Cover has a picture of my exact engine. Inside valve clearances are shown as 4-6 thou on both valves for my 20. but looking closer even worse. Operator manual was 4-6,9-11 on all four (12,15,20,21) as only listed once , not 4 times.. 276781 is 4-6,9-11 on 12 and 15 but 4-6 ,4-6 on 20 and 21. listing for each engine size.Go figure.

[KE4AVB]

Personally I don"t trust operator manuals as much as I trust the Power Portal site. Besides the Vanguard service manual don't really cover this engine. Briggs does need to take a serious look and update their service manuals. THe only new SM they have done in several type is the 12V300 one.

Well if you look back you see I asked for the type number and I would have looked up those specs on the Power Portal but since didn't post the type number I just left it alone.

I did just did a random type number check and these were the specs listed.

SKU 20M114-9289-41
Technical Specifications

Model Series 20M1
Power Lbs/Ft of Torque 13.5
Displacement 305
Oil Capacity 28 oz (0.8 l)
Valve Configuration OHV
Flywheel Torque 120 lb/ft (163.0 Nm)
Governor Arm Torque 40 lb/in (4.5 Nm)
Carb Mount 85 lb/in (9.5 Nm)
Plug Gap 0.03 in (0.75 mm)
Intake Valve .004-.006 in (.10-.15 mm)
Exhaust Valve .004-.006 in (.10-.15 mm)
Idle Speed 1750
Air Gap .010-.014 in (.25-.36 mm)
Flywheel Puller Part 19203
Flywheel Holder Part 19433
Connecting Rod Torque 100 lb/in (11.5 Nm)
Sump Torque 210 lb/in (24.0 Nm)
Head Torque 220 lb/in (25.0 Nm)

Also if you look in the Downloads under Briggs/Advance you will find ASPI 59 which has a lot of the other specs.

[38racing]

Type was 0937. Didn't think type would affect something like valve clearance. I'm going to reset exhaust to 10 just to see if it changes things. I'll watch that it still bumps for compression release.

[38racing]

Ok. No difference with exhaust at 10 thou. Choke and 3 primes it starts 2nd pull cold. Then problem restarting starts. Of course Murphy has come by to help. Made noise after starting. Found recoil dog in a hanging shield. When I shut it down I feel fuel coming out the intake. This time no muffler backfire but flamed out carb other starts it had to puff out the intake a couple times too.. Next pull it starts. Read last night that some of these models have head gasket issues. Can't do leakdown until I get a new tester. Murphy maybe. The hose taken from compression gauge leaks. It's release button allowed flow towards engine. Newer ones that I have are one way. For 20 bucks I also ordered a chinese carb to try.

[38racing]

Just tried again. Puffs out intake but not start. Hit electric and fires right up.

[bgsengine]

wonder if you maybe have a camshaft problem, or crank timing gear key... sounds a lot like a valve issue to me..

[KE4AVB]

Try changing the plug gap to .025 instead .030.

[38racing]

wonder if you maybe have a camshaft problem, or crank timing gear key... sounds a lot like a valve issue to me..

got me thinking that way too. still have the compression release bump at 10 thou. Occurs at 40 btdc. That makes sense to me if it sparks at 26 btdc. I did see a video where a guy claimed tecumseh he was working on sparks at 7 btdc.
It powers the 27 inch blower fine when it's running. I took the degree wheel off but could go back to that setup and test valve action if I knew when valves should open/close. Did a bunch of that 22 years ago when I raced gokarts for a couple years. I have the 5 hp version of this engine , brand new. I suspect that all the timings would be the same?