OutdoorKing Repair Forum Forums Repairs and Maintenance Questions On Ride On Mowers Questions On Ride On Mowers Frames best replacement engine?

I'm sick of repairing the engine in my cox lawn boss (B/S 16.5hp)and want to replace it before the summer growth starts. Looking for opinions on which is best to go with?
Options are B & S, Kohler & Kawasaki - I doubt if finances will stretch to a Kawa though.....need to be 15-20hp....willing to re-use b/s, have heard that the 16.5 was a bad engine
open to suggestions/advice

Can you tell us the Model, Type and Code for your Briggs 16.5 hp please? A couple of pictures would also help. I'm guessing from your comments that it is a Model 31C707 Intek, but we can't comment on how it compares with other engines, without knowing what it is.

Hi grumpy,its a 31E777 Intek, I've taken it out and put a spare 13.5 Intek in the cox but it doesn't have the grunt I need for commercial work.
The 16.5 has about 200 hrs on it, has blown 2 head gaskets and now has something more sinister wrong with it, one valve rod is disconnected - see photo - it started making a goddawful racket, lost power quickly so I shut it down. If you think its something I can repair myself (I'm no mechanic, but have all the tools)fairly easily I'll have a go...otherwise I'm up for a new donk

photos...






http://s1118.photobucket.com/user/redeye1964/library/Briggs%2016-5%20Intek

Thanks for those clarifications, Redeye. I don't have any confidence you can prevent any of the large Inteks from blowing headgaskets from time to time - IMO the design of the cylinder head and gasket has a weakness, in that there is insufficient support across the large span between studs, adjacent to the pushrod cavity. There seems to also be poor design in relation to the decompressor. These are areas where Briggs chose to make changes from the original Daihatsu design of the Vanguard, on which the large Inteks are based.

I have no experience with specific problems in the camshaft area other than a number of camshafts had lobes wiped off them, in fairly early production of those engines. I have been under the impression that this was overcome after a while. If you give us the Code we will know the date of manufacture, and should be able to establish whether your engine is early production.

Essentially, issues with blown head gaskets, decompressors not working due to exhaust tappet clearance being as little as 0.001" more than specified, camshaft failures in early production, and a fairly short fuel pump life, are the only characteristic problems I know of with the engine. The twin cylinder had a poorly designed air cleaner box and was prone to becoming dusted until the box was redesigned fairly recently, but that did not apply to the single.

The large Inteks seem to be cheap engines with questionable reliability due to the problems I've mentioned, but in general they can soldier on if they are repaired as often as necessary. For commercial service IMO you would have been considerably better off with a Briggs Vanguard twin, which is now and always has been manufactured in Japan to the original Daihatsu design. The Vanguard single cylinder engines have been made both by Mitsubishi and Briggs, and I am unclear on their quality record over time.

I suggest you have two alternatives here. You could verify that a V twin vertical Vanguard from their range (13 to 22 hp) is a simple drop-in fit then go that way, or you could dismantle the Intek, post pictures, and we could discuss what has gone wrong with its valve train. Time permitting, it seems more economical to find out what it would take to repair the Intek before making a decision.

the full details are - 31E777 0118 B1 1012157D

thanks for the photo fix grumpy, couldn't figure it out, has the posting procedure changed?

edit #2 - just found the new photo post

The engine's manufacture date was 15 December, 2010, so it is a very long way from being an early production unit. If you dismantle the engine, it will be interesting to see what has gone wrong with the valve gear.

Here is the illustrated parts list:
http://bsintek.basco.com/BriggsDocumentDisplay/18mnBGXPnfBhU7y.pdf

Here is the operator's manual:
http://bsintek.basco.com/BriggsDocumentDisplay/ioqsAJJU0HDjhJvcv4.pdf

If you are going to work on that Intek, you might need the workshop manual. It can be found in the subscriptions area:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=20019#Post20019

The file you need is called B&S 276781 Intek Single Cylinder OHV.pdf

(276781 is the Briggs part number for that manual.)

I took off the head today (and possibly didn't need to)when the engine is turned over the valve pushers are moving in/out so assume there is nothing wrong inside. Then noticed the cap wasn't on the end of the rod - you can see it in the 2nd photo above sitting in the bottom left. So am thinking that it somehow came off and caused the ensuing problems. Can I put it all together again, with a new gasket, and expect it to be fixed?
another shot showing the loose cap
[img:left][/img]

There are some slightly unusual features here that need to be sorted out correctly. First, the upper valve (exhaust valve) has a steel pushrod, with a painted red band around it, while the lower valve (intake valve) has an aluminium pushrod. You need to make sure they are in their correct places.
Second, the small round bit that fell off the top of the valve, shouldn't have been able to do that. It is supposed to be held in place by the rocker arm, which in turn is located by the pushrod. I don't see how it could come off unless the engine had an enormous exhaust valve clearance (which would make it clack horribly when it ran, like a vintage removal van), or the round bit is damaged, or perhaps if the valve retainer is failing and moving up the valve stem. (A less likely possible cause would be if the engine were overspeeded, resulting in valve-bounce, but that shouldn't happen on a governed engine unless someone intervened.) I think you need to remove the other (inlet) rocker and examine its little round bit for comparison with the one that fell off. I don't think you should reassemble the valve gear until the failure has been explained.

just bought a kohler sv470, (couldn't stretch the bank account to a kawa) hope they're better quality than the inteks - can't afford to have my mowers out of action (usually break down in the middle of summer when I'm going 6-7 days a week) will hopefully find the impetus to fix the intek...move to sunny jervis bay grumpy and open a repair shop in paradise!!

Had a generator with a no name engine on it almost identical valve train
setup one difference ... mine dropped the valve

I have no experience with the Kohler SV470 engine, Redeye. It is a more complex design than the Intek. I dislike the balancing mechanism it uses, which is rather similar to the old Briggs Synchrobalance, with large reciprocating weights operated by eccentrics on the crankshaft. The Synchrobalance tended to be unforgiving of low oil levels or failure to keep the oil clean. The Kohler has pressure lubrication and a car-style spin-on oil filter, but you still have to check the oil level, and change oil and filter at the recommended intervals, or it might end badly.

The other aspect I am a bit wary of is that the engine uses two camshafts inside the crankcase, operating the OHV rockers through pushrods, rather like some of the 1950s British motorcycles. In Kohler's case however this has enabled them to use a metal cam, riveted onto a plastic cam gear, pinned to a separate steel camshaft. This picture from the Kohler workshop manual also shows the automatic compression release mechanism:


The gerotor (i.e. Hobourn Eaton double eccentric rotor) oil pump, which has a plastic body with metal rotors, is threaded over and driven by the intake camshaft. See picture, also from workshop manual:


I would be interested to hear how your Kohler stands up to commercial service in the long term.