# Briggs 6hp on 99' Toro 20042... priming and valve lash?



## ls3c6 (Aug 4, 2011)

Primer doesn't seem to do much and makes it difficult to start, but runs perfectly once started... primer bulb takes 4-5 seconds to return to the normal position after pressing... does it need a new primer bulb?

Also I'd like to check the valve lash, from what i've read I should insert a screwdriver into the spark plug hole and set the piston 1/4" "in" past TDC, but what are the valve lash specs once I have the piston in this position?

Engine is a 12H802-1767-E1 any documentation?

thanks!


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## 30yearTech (Sep 14, 2006)

The primer bulb probably needs to be replaced as they should spring back quickly. 

This engine is an "L" head design and valves rarely need any adjustment, but here are the specs so you can check if you want.

Intake valve clearance: .005" - .007"

Exhaust valve clearance: .007" - .009"


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## ls3c6 (Aug 4, 2011)

OK... bought a new air filter, spark plug and primer bulb. I noticed when I had it running and RPM set to 3400 the butterfly on the throttle body would move slightly being regulated by the governor... should there always be some minor fluxuation? it wasn't surging but it wasn't dead on rpm either


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## 30yearTech (Sep 14, 2006)

3400 rpm's is too fast for this lawn mower. 2800 - 3000 rpm's is where it should be set.


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## ls3c6 (Aug 4, 2011)

Why is it too fast? Isn't the rule of thumb for a great looking cut on a 21" to set it 3400-3600?


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## duffer72 (Jul 23, 2011)

I wonder why also have always set L heads to 3400-3600 never had a problem


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## geogrubb (Jul 28, 2006)

I think it is some type of GOVMT std/reg for the optimum blade tip speed to be 19,000 fpm which on a 21in mower is about 3100rpm, I did have the calculations but lost them when old sys crashed. However, what each individual does is his or her own business(IMHO), some small engines can handle running hard some can't, I think it is more important to keep the blade sharp. Have a good one. Geo


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## 30yearTech (Sep 14, 2006)

ls3c6 said:


> Why is it too fast? Isn't the rule of thumb for a great looking cut on a 21" to set it 3400-3600?


No, not necessarily. There are a few reasons why you should not set the engine speed beyond what is recommended by the mower manufacturer. The actual specification for your mower is 3000 +/- 150 RPM. I was generalizing for Toro in my previous post, but was within the range. 

One reason is the governor spring that is installed on your engine is tensioned for this specific speed range, if you apply too much tension to it, the engine will not run smoothly and you will get some surging. Another reason is to stay within the maximum blade tip speed, this minimizes the possibility of blade failure if you strike a solid object. Maximum torque is developed at a much lower RPM and most Quantum engines peak at around 2400, lower speed setting keep the engine in a more optimum torque range. Mowers are designed to perform best at the manufactures specs, and different brands and types of mowers will have different specifications. Engines run cooler in the specified rpm range, consume less oil and fuel and have better wear characteristics.

A sharp blade and lower ground speed is going to deliver as good a cut as a blade spinning at the higher rpm.

You can certainly set the speed to whatever you choose, and the maximum setting should not exceed 3457 for a 21" mower (blade tip speed 19,000 feet per minute). Your recycler mower was designed and tuned to achieve the optimum cutting performance at around 3000 rpm.


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## ls3c6 (Aug 4, 2011)

OK... I replaced the primer bulb, air filter, spark plug and reset the RPM to about 3100... cut the lawn with it, few things I noticed when it FIRST starts you get one puff of black (rich) and when you disengage the self-propel you hear a slight blub from the engine (less load?) Other than that it works fine and rpm is steady, I verified the primer was working by pressing it with the engine running and it puffed black and lost RPM. I also notice on any incline it tends to burn a tiny bit of oil... I wonder if the previous owner overfilled it.

I will try to see how difficult it is to start once cold again pressing the primer 5 times and pulling the cord. 

I also had some problems with the personal pace drive, this is a Toro 20042 1999 model year and after replacing the washer clutches, rocking keys and rubber o-ring on both sides the self-propel works properly... EXCEPT when engaged I hear a slight whine like that of those battery powered powerwheels toys... is this an indication of a problem inside the transmission? I see lots of reports of this being "common" with the single speed toro personal pace trans and the 3spd on my suzuki powered Toro is very similar except it doesn't make any type of whining noise.

thanks again!


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## 30yearTech (Sep 14, 2006)

Some of those transmissions can be kind of noisy. I usually see this as a need for some fresh grease in the gear box. Four screws on the bottom plate of the transmission and you can gain access clean out any dried up grease and refill with new grease. Just any GP grease will do, that usually quietens them up.

Generally these engines only require 3 primes for a cold start, if 3 is not getting the job done, you may have a slight leak where the air filter mounts to the carburetor, and you may need to replace the mounting gasket.


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## ls3c6 (Aug 4, 2011)

OK i'll goop up the transmission with some new grease, just coat the gears? 

I noticed since it's been shut off a few hours a few drips of gas dripped out of the primer bulb, however prior to shutting it down I pressed it a few times to verify it was working properly... is that why or is something else wrong!?!


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## 30yearTech (Sep 14, 2006)

Primer also doubles as the atmospheric vent for the float bowl of your carburetor. If it continues to drip fuel, then the inlet needle and seat in your carburetor may not be sealing good.


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## ls3c6 (Aug 4, 2011)

OK cut with it again, primer isn't leaking and it started on 3 primes and a single pull. Lubed up the transmission and spindles with grease and it isn't making excessive "power wheels" noise, but if you listen closely you can hear some rotational whine from the outer spindles.

One thing I am noticing is under moderate load I hear some "tapping" from what sounds like the top of the engine, it doesn't lose RPM or knock just a light tap tap tap during operation when loaded... is this a problem?


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## 30yearTech (Sep 14, 2006)

I would not worry about it, if it does not sound like an engine knock. May be a little pre ignition, may want to try the next higher grade of gas.


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## ls3c6 (Aug 4, 2011)

I'm using fresh 87 octane which has never been an issue in any mower, it's e10 of course but does this engine require more octane? It's a very soft tap and seems like it comes from near the flywheel/engine cover... maybe even the governor arm assembly i'll take a closer look


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## 30yearTech (Sep 14, 2006)

nope, 87 is fine!


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## ls3c6 (Aug 4, 2011)

Found a bunch of gunk on everything when I removed the top engine cover, especially at the base of the governor arm where it goes over the pin in the engine. I removed the nut and removed the arm for cleaning... not sure I put it back on right though... I tightened the fastener with the pin in the engine as much counter-clockwise as possible. When I started it back up RPM was where I set it before so is it ok?


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## 30yearTech (Sep 14, 2006)

If the engine is running in the RPM range specified, then it's fine.


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## ls3c6 (Aug 4, 2011)

Well now that it's all fixed... I still find it vastly inferior to my Suzuki 4 stroke powered 1988 Toro 20622... the deck might be a little better I dunno, but this 20042 doesn't do it for me.

Is there another RWD 21" self-propelled mower that will far exceed the useability and performance of the 20622?


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## 30yearTech (Sep 14, 2006)

ls3c6 said:


> Is there another RWD 21" self-propelled mower that will far exceed the useability and performance of the 20622?


I don't think so, at least in my opinion the Suzuki engine is hard to beat.


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## ls3c6 (Aug 4, 2011)

30yearTech said:


> I don't think so, at least in my opinion the Suzuki engine is hard to beat.


Should I seek out a 2 stroke Suzuki... even better than the 4 stroke? I'm an IT guy so I find it hard to believe that since 1988 they haven't made a far superior machine


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## geogrubb (Jul 28, 2006)

Since 1988 marketing has changed, unless it is commercial grade it isn't supposed to be great, just good enough to get by so it will break and you will buy a new one. I have had a lot of mowers pass through my back yard and prefer Lawnboy F series 2-cycle. Have a good one. Geo


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## 30yearTech (Sep 14, 2006)

ls3c6 said:


> Should I seek out a 2 stroke Suzuki... even better than the 4 stroke? I'm an IT guy so I find it hard to believe that since 1988 they haven't made a far superior machine


Superior is the key, I think those old Suzuki units were about as good as they get. I do however consider some of the newer units to be just as good.

I do like the newer recycler units a bit more then the older mowers (as far as quality of cut is concerned). I am real fond of the personal pace self propel as compared to the old 3 speed drive. I just do not count any of these as being far superior, more like on par with the older units.

Parts for Suzuki powered Toro mowers are getting harder and harder to find, and they are expensive as well. 2 cycle units were discontinued I believe in 2004, so you may be hard pressed to locate one, and they only used that engine on the commercial mowers when they stopped making them. The Honda powered Toro mowers have a reasonably good engine, and I have no real issues with the Briggs powered units.


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## ls3c6 (Aug 4, 2011)

I'm surprised my older 20622 with the bagging chute and no kickers mulches BETTER than my 20042 with no chute and no kickers


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## 30yearTech (Sep 14, 2006)

ls3c6 said:


> I'm surprised my older 20622 with the bagging chute and no kickers mulches BETTER than my 20042 with no chute and no kickers


It may depend on the type of grass your cutting. The Recycler was developed and tested primarily for St. Augustine grass, and extensive testing was performed at Texas A&M university. The old super bagger deck used on the 20622 without a mulch plug tends to drop a lot of large clippings back on the lawn at least when cutting without a bag on St. Augustine grass. The clippings like to collect in the bag chute and then fall back out by the right rear wheel while mowing. The decks with kicks install make a big difference when mulching, but do not excel at bagging. It's a trade off, the old super baggers were very popular and the design was around for a long time. That mower deck was not retired until I think the 2005 model year, but it's still used on the commercial mowers.


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## ls3c6 (Aug 4, 2011)

I live in West Michigan cutting KBG/Rye @ 3.0-3.5" and I only mulch... I do experience some buildup at the chute on the 20622 but I cut about 15,000sqft and I release the clippings while mowing 2-3x and run over them. 

The "super recycler" 20042 leaves a cut similar to the 20622, but I see clippings in rows in lines where the wheels rolled along the grass. Both mowers have sharp blades, but the blade on the 20042 has a decent amount of sail wear... maybe put a new blade on the 20042 and see how it compares then?


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## 30yearTech (Sep 14, 2006)

The blade can make a huge difference. You will notice that the blade on your 20622 has quite a bit of lift as it's really designed for bagging, the blades for mulching have far less lift.


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## ls3c6 (Aug 4, 2011)

So in theory if the 20042 had a new blade with zero sail wear it should easily outperform the 20622?


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## 30yearTech (Sep 14, 2006)

The blade is designed to work in tandem with the kicks on the mower deck to create an air flow that causes the clippings to be redirected several times back into the blade so they are cut and re-cut several times into a fine mulch and then blown back into the turf so that they come in contact with the soil and decompose faster as well as deliver a more bagged appearance.


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## 30yearTech (Sep 14, 2006)

Can you tell I was a Toro dealer and sold them for around 30 years?


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## ls3c6 (Aug 4, 2011)

yeah lol, just surprised the 20622 which is meant to be a bagger does so good at mulching... i'll get a new blade for the SR and see if it exceeds the cut of the 20622


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## 30yearTech (Sep 14, 2006)

I installed a recycler kit on my old super bagger deck about 7 years ago and never looked back. I think the quality of cut rivals the mower when I used a bag, my old Toro is a 1986 model and I love the cut it provides. I also have a 22" steel deck model that I think does a great job, considering what it cost next to my old super bagger.


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## ls3c6 (Aug 4, 2011)

How about the brand new super recyclers? Will I be disappointed dropping the cash on one of those? They're selling them for about $450 this time of year


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## 30yearTech (Sep 14, 2006)

Well I can't speak of any personal experience with the newer Toro's except for the 20192. I have mowed with one of these and I really liked it. The other units are so new I have not had any experience with them as of yet. I would like to think that any Toro would be exceptional, as for the most part they have always been very good units. I like the company, as a dealer they were always the easiest to work with, and gave the best customer service.


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