I have had starting issues with the 17hp Briggs and Stratton OHV engine in my Toro for quite some time. Battery, starter, solenoid and cables have been replaced however problem still exists. When cold, the starter turns the engine maybe half a turn and then stalls. After several attempts it will usually start. The starter cranks fine when the engine is hot.
After reading though some of the posts on this forum it appears the engine may have some form of automatic decompression system, although I am not 100% sure. Numbers from engine are 31F777 0123E1 040413ZE.
Could it be that this decompression system is faulty? I have also seen references to adjusting the valve clearances.
The Briggs Intek engines have several characteristic sensitivities. There are two that seem to be relevant here:
1. The engine cannot crank if the decompressor is not operating. The starter motor does not have enough torque to turn it over. If you try anyway, you will destroy the starter motor, the starter motor electrical cable, and before long, the battery. It is much cheaper to keep the decompressor working.
2. The decompressor will not work if the exhaust valve tappet clearance is even 0.001" more than the maximum specified (0.007"). Because the stamped steel rocker arms and their pivots tend to wear a fair amount, especially from new when small burrs may be present, it seems the only way to keep the engine starting, and the wiring and starter motor flame-free, is to keep a close watch on that clearance. If you can keep it at a steady 0.006", all will be well. If it ever reaches 0.008", the decompressor will not work, and bad things will follow.
So, in summary, it seems extremely likely that your exhaust tappet clearance is currently slightly more than 0.006", and you need to adjust it carefully. The minimum specification is 0.005", and it seems a good idea to set it carefully for that clearance, so it will take a bit longer before the decompressor stops working again.
Briggs specifies that the tappets on that engine must be adjusted annually, and I suggest you adhere to that.
The Intek engines have some other unlovely features as well as that one. In particular, I suggest that you have a very close look at the air filter housing. Many of them do not seal around the filter element, resulting in the engine becoming dusted (excessive cylinder wear due to inhaling dusty air).
Thanks for your quick reply. I wish I had found this forum earlier too....
I will check the tappet clearances and let you know how I go - obviously a common fault. I am pretty annoyed because we have always had it serviced (by one of two different shops) and no-one has picked up on this problem. Just wanting to sell me a new mower I guess.
As for the air filter housing, is this something that can be repaired or is a new housing required?
Your report on what you find, with regard to the current exhaust tappet clearance, the engine's behaviour when you correct it, and the sealing status of the air filter housing, will be appreciated by our members, Andy.
The existing air filter housing may function correctly if you assemble it very, very carefully and check it regularly - unless it has been damaged by heavy-handed treatment by now. The current production Inteks have a redesigned air filter housing which looks a more practical design at least in their publicity pictures. I do not know whether it can be retrofitted to the older engines - that sounds like a good solution if it can be done. If you find the answer to the retrofitting question, please let us know.
I am attempting to adjust the tappet clearance and I think I may be going about it incorrectly. Turning the inner adjustment screw (torx) does not seem to change the clearance. Turning the outer nut seems to adjust the clearance. It appears a bit counter intuitive. Either that, or I have totally got it wrong (likely...)
You are correct Andy, on those Intek engines that have the Torx screw, it is just the locking device, and the hex head screw outside it is the tappet adjustment. Here is a video showing how to make the adjustment (warning: do not follow his advice to set the exhaust tappet to 0.004": this is below minimum specification, and could conceivably lead to a burned exhaust valve):
After I made my last post, I found a similiar video. Better to ask a dumb question than to make a dumb mistake....
Anyway, I set the clearance to 0.005" and it now starts like a dream! Thank you very much for your help.
I looked again at the air cleaner housing and concur it is not the best design. I wonder if putting a small smear of grease on the seal would help? What do you think?
I've done some more reading on the Intek air filter problem, and every reference to it I have found, has related to the twin cylinder version. Here is one description of the problem (read mroman59's explanation of what it is and how to fix it): http://www.mytractorforum.com/showthread.php?t=263375
He says the spring-clip that retains the top cover of the filter box has insufficient tension to press the element against both the top and bottom of the filter box, so there is air leakage past the filter's ends.
Mine does not have a yellow clip and is obviously single cylinder. It is an all plastic affair with a kind of over centre locking arrangement for the air filter cover. It may be ok, it just feels like it is cheap and does not lock down with a positive feel.
I would suspect that if the plastic shroud was twisted or otherwise damaged, it would not seal very well. Also if care was not taken to install and seat the air filter element correctly. Luckily I have always looked after mine and the plastic has retained its original shape.
After 9 years, I have not had any issues with dust etc. in the engine. I am so glad the starting issue has been rectified though. We should receive our new Greenfield in a few weeks so the Toro will be up for sale. It will be a bit sad to see it go - I've spent many hours with my bum on that seat.....
My theory is that people who buy their mowers new, mostly replace them with new ones when they lose confidence in the old ones. I suspect once that Intek let you down, you weren't going to be happy with it even if the failure was fixed. In my opinion the Intek is at the lower end of the range of modern engines when it comes to reliability in the field. In amongst the other problem areas we talked about, we didn't ever get as far as discussing the cylinder head gasket failure record, which seems to be woeful.
I'm moderately familiar with the Greenfield mowers, just from the cases we see here at Outdoorking. Provided you choose a good engine for it, and understand one or two little foibles of the mower itself, you'll probably be very happy indeed. It is potentially a durable machine, provided the servicing is expertly done in a timely manner. I am not especially confident that the person who has been servicing your Intek is the best possible choice.
Thank you for contributing this thread, Andy. I will now close it. If anyone needs to post to it, just PM a moderator.
