Help with hard-starting Briggs on a Toro - 6.75HP

[btanchors]

I have a Toro Super Recycler - it's probably about 8 or 9 years old. I am having a bear of a hard-starting problem. At first, a couple years ago, it was hard to start, but only when warm. Now, it is hard to start all the time, warm or cold. And when I say hard to start, I mean it - I just gave up today after probably 30-40 attempts.

Eventually, I can usually get it to start - but only after lots of priming and pulling. During the starting attempts, I can tell when it's getting ready to finally start - it starts "spitting" or having very minor backfires - and some smoke coming out the exhaust. When it finally catches, more smoke come out the exhaust. Once it catches, it runs well and does not stall. It has plenty of power. But if I shut it down, I am back to the starting problem again.

New spark plugs, air filter, and fresh gas doesn't help. It seems to to have good compression, judging from the resistance when pulling. Given the age of this mower, I don't want to put lots of money in it, but on the other hand, I am so frustrated with it that I am tempted to just take it to the dump. This would be a shame because the mower is in pretty good shape and runs great - Once it starts.

Any thoughts on what's causing the hard starting?

 

[Old Mustang Guy]

This does not really address the root problem but have you tried a different oil? I have that same motor on my Toro. When I switched from 30 wt. dino to a synthetic 5W30 the starting improved dramatically.

 

[btanchors]

Old Mustang Guy - I don't think the oil is the problem - but I have used mainly two different oils - Mobil 1 10W-30EP previously, currently using Amsoil MCT 10W-30.

 

[01rangerxl]

This is the kind with the square panel air filter with the primer on the front of the housing?

Have you confirmed the primer is getting fuel into the carb?

Remove the entire air filter housing. Spray Deep Creep or gas in the carb, then choke it with your hand. If it starts easily, you have a primer/carb related problem.

How hard is the recoil to pull? Sometimes bad camshafts make these engines difficult to start.

 

[Boomer]

The fact that its smoking when it finally starts sounds like it is flooding out quickly. Do you keep the choke on the whole time while you are trying to start it? Or do you pull the throttle back to "Run" after a few pulls?

 

[oggb]

Magneto/coil/whatever that thing is could be bad. Take the spark plug out, keep it in the boot, ground it to the mower (or whatever it is) chassis and have someone pull it. See if you get a spark. If so, that's probably not the problem.

If it has a strainer in the gas tank make sure that isn't clogged.

Clean the carb out as well as you can.

 

[btanchors]

01rangerxl - This is not the one with the square panel air filter - ironically, I have another Toro that has the square panel filter - it starts fine.

This one has an air filter that is kind of an elongated oval - with a foam pre-filter on it.

There is no choke on this model - just a primer bulb.

 

[javacontour]

Does this have a carb bowl? If so, is the float or its valve sticking?

I had a 6HP B&S with a similar air filter and it matches your description, no choke, but did have a primer bulb and had to open the bowl once or twice a year and clean it out with carb cleaner until I finally rebuilt the carb.

I didn't have any issues after that.

I could get it to run a while by whacking the carb with the handle of a screwdriver to free the valve until it would stick again.

I could clean it and it would last most of the summer, but need another cleaning before I stored it away. No amount of carb cleaner in the fuel would keep it clean so it must have been a bad valve. Once I rebuilt the carb I never had another issue with it.

I got pretty good at removing the bowl with the carb still on the engine, spraying it with carb cleaner and getting the bowl back on

 

[dwendt44]

Weak spark or dirty carb.
I'd try a strong dose of SeaFoam in the gas.
A shot of starting fluid until it's straightens out.
Try setting spark gap to the minimum for that motor.
Check resistance reading from plug wire end to ground, I've heard of rare cases where the end of spark plug wire (cap) that fit on
plug was bad.

 

[100td]

As it an older engine and has probably done some work, you may find the valves need the ends ground off them as you probably have no valve clearance anymore. When the valves "ride" combustion gas is blown back down the intake and blows fuel in/out of the carby and makes them very hard to start. i had this problem on my 20 year old 4hp I/C engine, just got harder and harder to start over a couple of years until I just couldn't get it going. I pulled the head off ground a bit off the end of the valves to give them some clearance at TDC and put it back together with the old gaskets and all, WOW, what a transformation, starts so easily, more power, just like new.
If you take the aircleaner off and give it a big pull, or have someone do this, you may see some blowing out of the carby, this is caused by the valves and seats which have now worn down so there is no clearance between the pushrod and the end of the valve. Note, I did not grind or lap the valve faces, only ground a bit off the end to allow some clearance. Yes, if it was someone else's then a proper lap or grind should have been done with gaskets etc.

 

[btanchors]

OK,

I found info on how to adjust the valves. One valve (I think the exhaust) was spot on. The top one (I think it is the intake) was a bit too wide, but not by all that much. So much for my theory. I thought it might be the valves because it spit/popped through the carb while trying to start it.

Anyway, I tried what some suggested - pouring gas directly into the air intake. I removed the air cleaner, and accidentally spilled too much, so much that liquid gas got into the combustion chamber, making it impossible to pull the cord. After clearing that up, I gave it a few more pulls, and it finally started! This is after literally over a hundred attempts. So it appeares to be a fuel/carb problem.

The strange thing is that I looked into the air intake after removing the air filter - the primer WAS pushing some fuel in. Also, the primer bulb has a small hole in it.

I figured I would order a carb overhaul kit, but discovered a whole new carb is only about $40, so I think I will order one and install it over the winter season.

At any rate, thanks for all those who replied - it looks like a fuel problem.

 

[wolfc70]

Originally Posted By: btanchors
OK,

I found info on how to adjust the valves. One valve (I think the exhaust) was spot on. The top one (I think it is the intake) was a bit too wide, but not by all that much. So much for my theory. I thought it might be the valves because it spit/popped through the carb while trying to start it.

Anyway, I tried what some suggested - pouring gas directly into the air intake. I removed the air cleaner, and accidentally spilled too much, so much that liquid gas got into the combustion chamber, making it impossible to pull the cord. After clearing that up, I gave it a few more pulls, and it finally started! This is after literally over a hundred attempts. So it appeares to be a fuel/carb problem.

The strange thing is that I looked into the air intake after removing the air filter - the primer WAS pushing some fuel in. Also, the primer bulb has a small hole in it.

I figured I would order a carb overhaul kit, but discovered a whole new carb is only about $40, so I think I will order one and install it over the winter season.

At any rate, thanks for all those who replied - it looks like a fuel problem.


Adjusted Valves? Is this the OHV Intek? If so, check the needle and seat for the float. Mine had some gunk in there, and it would slowly trickle fuel into the carb body and manifold. This would flood the engine during hot starts. I wondered for awhile why I never needed to prime the engine when it was cold.

Don't waste your money on a new carb. A rebuild kit is like $8-12 USD and this carb is very simple/easy to work on. And yes, there is supposed to be a hole in the middle of the primer bulb.

Good luck.

 

[btanchors]

wolfc70,

I am not sure if this is an Intek or not. I do have an 18HP Intek, and it has the "Intek" logo all over it. The one with the problem is 6.75HP and it is on a Toro Super Recycle mower, the top of the line in the consumer grade mowers.

I am glad you told me the primer bulb is supposed to have a small hole in the middle of it, I thought that it might be contributing to the problem!

Now that the cutting season is over in my neck of the woods (near Washington DC), I am inclined to agree with you - I will just order the overhaul kit, which I found online for $15. Although I am mechanically inclined, I have never overhauled a carb before. Is there anything online that can prep me for doing it?

Since I won't need this mower until April, I now have four months to get this done!

 

[dwendt44]

Get a good brand name carb cleaner spray. A small acid brush (auto parts store)a piece of multi strand wire.
Wear eye protection.
Take notes or pictures (preferably both).
TAKE YOUR TIME.
Don't over tighten screws.
Use a manual of some sort.
The wire is so you can use one strand to push through a plugged
jet or orifice. The copper wire is less likely the mess anything up.

My 2¢

 

[wolfc70]

Originally Posted By: btanchors
wolfc70,

I am not sure if this is an Intek or not. I do have an 18HP Intek, and it has the "Intek" logo all over it. The one with the problem is 6.75HP and it is on a Toro Super Recycle mower, the top of the line in the consumer grade mowers.

I am glad you told me the primer bulb is supposed to have a small hole in the middle of it, I thought that it might be contributing to the problem!

Now that the cutting season is over in my neck of the woods (near Washington DC), I am inclined to agree with you - I will just order the overhaul kit, which I found online for $15. Although I am mechanically inclined, I have never overhauled a carb before. Is there anything online that can prep me for doing it?

Since I won't need this mower until April, I now have four months to get this done!


The main thing is to make sure you take photos/draw picture of how the governor linkage is hooked up. This is where most people get frustrated and make mistakes that can ruin the engine (over revving).

Just take you time and be patient, watch how things come apart, take pictures if it will help you.

 

[NHHEMI]

See if you can find any OMC 2+4 fuel conditioner at a local marina/marine supply outlet? You can get it online if not. Get a bottle and treat your gas with it. Do whatever you have to so the mower starts and then run it for a bit with that stuff in the gas. You might want to consider a double dose of the recommended standard amount. That is what I do in really bad situations.

I have had amazing results with that stuff cleaning out the carbs and returning the engine to a proper operating condition on yard equipemt( lawn mowers, snow blowers, weed whackers, etc... )and marine engines that gave me starting problems due to dirty/gummed up carbs and fuel systems. Both 2 and 4 stroke/cycle. I have even seen it save those cheap 2 cycle weed whackers that only are good for a year( i.e. they gum up so bad after sitting over the winter, even with the fuel drained/treated, they won't start ).

It all comes down to getting the engine to actually start up so the gas can run through with the 2+4 in it. As long as it is not a mechanical issues this will help if anything will. It works better than anything else I have ever tried including Seafoam( and I am a big SF fan ). Have seen it save a lot of equipment though dead or in need of repairs. Just run it for a while so it can do the job.

Pretty much if you can get it to start go mow the lawn and by the time you are done you should notice a big improvement in overall engine operation. Should be smoother and start easy(ier).

 

[boraticus]

Save your money. Liquid magic will not do anything for the condition your dealing with.

Follow instructions below and you'll at least KNOW your carb is good. If you still have a starting problem, I'd be looking at the valves.

I know you said you adjusted them but they may not be right. The valves need to seat in order to achieve sufficient compression for the engine to start. When you adjust the valves, they should be adjusted toward the loose side of the specifications. As the saying goes, "Tappy valves are happy valves." Did you have the piston positioned at TDC on a compression stroke when you set the valves? My B&S manual says that the piston should be six degrees past TDC to set the valves. Both valves should be loose on a compression stroke.

I adjusted the valves on my B&S snow thrower engine a couple weeks ago. It's a bit tricky to do right because the lock nut can effect the set screw setting. It took me three times to get one valve set just right.

Either way, clean the carb as per below instructions then move on to the valves. If the problem still exists, check the electrics.



Originally Posted By: dwendt44
Get a good brand name carb cleaner spray. A small acid brush (auto parts store)a piece of multi strand wire.
Wear eye protection.
Take notes or pictures (preferably both).
TAKE YOUR TIME.
Don't over tighten screws.
Use a manual of some sort.
The wire is so you can use one strand to push through a plugged
jet or orifice. The copper wire is less likely the mess anything up.

My 2¢

 

[kcfx4]

checked gaskets? the gasket behind the air filter plate could well be the culprit! as mentioned b4 the magneto could be the culprit as well, yet i doubt it, as if it were, typically youd run just fine til warm, then die. but youre not going to "pour" in a miracle via gas tank nor sump

 

[kcfx4]

is it a diaphram type carb? could be a pin hole in diaphram?

 

[btanchors]

All,

Please calm down, we're all enthusiasts here...I didn't intend to start a controversial discussion.

I do think chemical solutions have their place, and I haven't tried one yet. If my circumstances were different I probably would have tried it already, but I have not.

I do suspect there is a significant problem somewhere, as the problem is consistent, and has been progressively getting worse over time. A couple of years ago, this engine started fine when cold, the only problem was starting when hot. Now, it doesn't matter whether it is cold or hot.

I've already completed normal maintenance on this unit, which I do prior to putting it in storage during the winter season, which consists of cleaning the unit off, replacing engine oil, spark plug and air filter, and adjusting the valves.

My plan is to obtain an overhaul kit (I located one for $15), and remove, disassemble, and clean the carb (after taking lots of digital pictures first!). I probably won't get around to this until January, though. The timing is right given I won't need this mower until April.

Had I given it some thought earlier during the cutting season, I would have attempted a chemical solution - if that had failed, the next step would have been to remove the carb and clean it anyway, meaning the worst that would happen is a loss of $$ for the chemical, whichever one I would have tried.

Many thanks for all the advice. I do intend to follow up on this thread, but it will likely be a month before I get to it.