OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Briggs and Stratton Missing on one Cylinder

Hello All,

I am new to this forum. I am an active 71 years of age and enjoying retirement with my wife on our 5 acre rural-residential block.

I have a Briggs and Stratton Model 445877 26 HP vee-twin engine (type 0135B1) (code 080110YG, powering a Greenfield rideon mower.

I hope that someone can help me with a problem which recently arose.

Engine began missing on one cylinder - hot and cold. Engine has done only 102 hours and is regularly serviced. I initially suspected a plug, but both plugs seem OK and swapping them between cylinders makes no difference - left hand cylinder still misses. (At 52 hours, this engine sufferred a catastrophic governor failure requiring a new short block by local dealer under warranty.)

A rough compression test, (finger over plug hole while cranking), shows LH cylinder pressure is much lower than RH.
When engine is running exhaust gas pressure of RH cylinder is much higher than LH one.

I am wondering - blown head gasket/scored bore/bad valve/bad valve seat/no valve lash/broken compression ring/s/- are there simple steps I can take to identify the problem source?

Any and all help will be appreciated.

Thanks in advance

mustang

As your engine is a ohv motor I would strongly suggest that your headgasket could be blown on the left side, as its quite common, hoever it would also be worth taking a quick peek under the rocker cover on the left side to make sure that one of the pushrods hasnt come out.

Joe,
Thanks for your input.
I had a look at the valve gear on the LH cylinder - all seems to be OK.
When running the engine I notice that the LH rocker cover becomes quite warm after a few minutes, while the RH cover remains cool.
Is this normal for these engines?

THanks and Regards,

mustang

The engine you have has a reputation for blowing the head gasket, usually from the combustion chamber into the pushrod recess. Escaping hot gasses passing into the pushrod cavity will pulse into the rocker cover as well as into the crankcase. Hence the symptom you describe is consistent with a blown head gasket, but it sounds as if it is rather badly blown for heating of the rocker cover to be noticeable.

It is quite undesirable to operate the engine with the gasket blown, because the hot gas will erode the cylinder head or the top of the cylinder block, and this is relatively difficult to fix.

To diagnose the fault all that is usually necessary is to establish that the compression pressure is lower on one cylinder than the other, but the tappet clearances are correct on the leaky cylinder. When you have verified this it is still possible it is a leaky valve or leaky piston rings rather than a gasket, and if it was, say, a side valve Briggs engine, it would be a good bet this is actually what has happened. However since the engine has a reputation for blowing head gaskets, and that is an easier problem to fix compared with either rings or valves, it would be usual practice to remove the cylinder head and inspect the gasket. I think most mechanics would replace the gasket and retest the engine even if they could not see leakage marks on the gasket, just because of the engine's reputation.

You have also said the engine had its short block replaced by a local repairer. In other words, the head gasket was fitted by a local repairer, while the rings and valves were fitted in the Briggs factory. I think statistics would show that repairers are rather more likely to make mistakes, than the North American Briggs factory production lines are.

Since my last posts in this matter, I sent the machine in to a local authorised B&S repairer who advised me that the valve guides are worn to the point that intermittent misses are occurring on both cylinders once the engine warms up. He has contacted B&S in the USA regarding a warranty claim for remedial works and they have agreed to replace with new all defective parts.

(I might have been a little lucky in all of this as the machine is at the end of its 2 year warranty period this month.)

However, as it has done only 102 hours since new, and had a governor failure at ~ 50 hours I am wondering if I have a lemon, or maybe current B&S engines of this type are not what they are cracked up to be.

I do not know which particular alloys B&S use for their valve guides in these engines, but I do know that with air-cooled engines it is necessary to know what you are doing in this area, particularly in relation to the exhaust valves and guides which are exposed to very high temperatures. I understand that these working temperatures can range from around 600 to 700 deg C.

Funnily enough, the reason I purchased this current engine was because of the great performance I have experienced in the past with previous B&S single cylinder machines of various sizes.

Such appears to be life.

Any thoughts, anyone?

Regards,

mustang

At this point I'm not confident that the problem description you have received is necessarily entirely accurate. I'm not accusing your repairer of protective colouration of the facts, but dealers in some products engage in this kind of thing routinely. Anyway, if the engine is being repaired on warranty, you are not out of pocket and you can hope the work will be done more successfully this time.

There are two "brands" of B&S OHV large engines: Vanguard and Intek. The Vanguard engines are designed and built in Japan, and have quite a good reputation. The Intek engines began as Vanguards but the design was revised by Briggs to make them cheaper to produce, and they are made in the US. As far as I am aware they have a bad reputation.

Post-edit: These pictures from spare parts listings may give you an idea why the Intek engines blow head gaskets and the Vanguard ones do not. Here is a 25 cubic inch Vanguard head gasket - I have added a red circle to show where it usually blows, from the combustion chamber to the pushrod chamber:


Here is an 18 cubic inch Vanguard head gasket - as far as I know these gaskets do not blow, though I have read about one slight oil weep:

I too would doubt that just the valve guides would be the issue.
Being OHV they should be a lot less prone to wear than a side valve motor.
Without looking up the parts list, are the guides even a replaceable part??

There are lemon laws, i would check around in your state and find out if they apply to this engine you bought. Whatever consumer group that would cover it.
The govenor issue and now this supposed guide issue. When you get the engine back what warranty will be left?? Just the 3 month warranty from the shop that does the repair?? I would be asking for another 12 months or more.

You have had a bad run and it would not be unreasonable to expect that Briggs take the engine back and replace it with something that will outlive its warranty period and give a service life that would be expected of what is meant to be a quality product.

2 major repairs in 2 years and close to 100 hours. That is bad. A half the price chinese wonder would do better than that.

So after you get it back you could at best expect another 50 hours and under 12 months out of the engine.

Say if it did make the 3 year mark, what did it cost new?? im tipping thats more than $500 a year. Not good enough, im sure you could have got a contractor in to mow your lot cheaper than that.

My special thanks to both grumpy and Rodeobob for their inputs. I will look up the Queensland lemon laws to see what gives.

The 2 year warranty on the engine expires on 14 th May 2012. The engine model is 445877 - 0135 - B1, powering a Greenfield Model 34 Fastcut Ride On Mower. I am pretty sure that it is an Intek-badged unit.

My downloaded B&S parts list for the 445800 series engines does not indentify valve guides as separate parts. My local B&S repairer indicated to me that B&S supply new heads and valves as complete asemblies in cases like mine.

Regarding prices, I purchased the Ride On Mower new - they were listed at $7500 RRP, but I traded in so that I paid less than that in May 2010. Of that price, roughly how much would have been the engine cost - about $2000?

Anyway, onward and upward.

Regards,

mustang

Hello to all (grumpy and Rodeobob in particular),
Just to keep you all up to date. After some delay, B&S USA eventually provided a complete new 26 HP vee twin engine of the ELS type as a replacement under warranty. So, I now have another engine with a 2 year warranty. Apparently, the ELS is a development of the basic Intek type, with chrome plated exhaust valve stems, larger cooling fan, a halfway decent air filter system and improved oil pump output among other things.
We shall see how we go.

Regards to all,
mustang

Thanks for updating us, mustang. If they have fixed the air filter issues, that is a major step forward. It does not tell us what they have done about the head gasket problem, and the ultra-finicky tappet adjustment to get the decompressor to work, however. Please update us when you start to use the mower: some pictures of mower and, especially, engine, would be appreciated as a conclusion to this thread.

Hello again, grumpy.

I would have responded earlier to your advices of May, but just lately has been a very busy time for my family.

Anyway, the new ELS engine seems to run well enough - although it is difficult to start without some choke, even when warm. This engine also idles at a higher RPM than its predecessor.

Attached are some photos of the installed engine and machine as requested, to round out and close the thread. B&S have reworked the air intake system and filtration arrangement - it seems better designed to resist bypass dust entry. They have also added an electric fuel pump. The exterior dimensions of this engine are greater than the one it replaced, requiring the dealer to rework the engine cover hinges to allow it to close.

Thank you for your past advices. (I look forward also to some further advices in another matter which will be the subject of a new thread - "Briggs carburettor setup problems"









All the best,

mustang

Thanks mustang. A couple of questions though:

1. Is that air filter a foam pre-filter wrapped around a paper filter? If so, is the foam section oiled? Can it be removed to wash and re-oil it? Or do you have to replace the whole thing at frequent intervals?

2. How often does the oil filter have to be replaced? Does that coincide with every oil change?

3. Are you supposed to switch on then wait for the electric fuel pump to operate before starting the engine?

Aside from that, I suspect running slightly lean is something we are all having to learn to live with, due to increasingly stringent emissions regulations on mower engines that have only simple control systems and no exhaust after-treatment. Cars of the mid-1970s had similar emissions controls, and much the same issues with regard to slightly inferior driveability.

Hello grumpy,
Your response quick as a flash as per usual. Thanks.
To answer your questions plus some general info -
- engine is B&S Model 44P777-0177-B1 "Intek" ELS Professional, 724 cc, 26 HP, Vee-twin
- this engine series features a larger cooling fan than the standard models
- this engine series also features an electronic fuel management system, which is supposed to monitor engine temperature, engine speed and battery voltage to adjust choke during starting and warm up. There is a dashboard-mounted manual choke control lever which must be used to start the engine, and then quickly set to off when engine starts.

- electric fuel pump appears to be required as the carburettor intake level is above the bottom of the fuel tank on this mower. (There is no wait for fuel delivery, engine start is immediate using manual choke. Also B&S guarantee fuel delivery on a 15 degree mower operating slope.)
- air cleaner foam pre-filter is a dry element, which I clean frequently in dry dusty conditions. (OEM says clean each 25 hours, and replace annually.)
- air cleaner main element is the usual dry paper type, which I clean along with the pre-cleaner. (OEM says clean and replace as for pre-filter above.)
- engine oil change is done at 6 monthly or 50 hour intervals. (OEM says every 12 months or 50 hours.)
- oil filter is changed along with engine oil, every 6 months. (OEM says every 12 months or 50 hours.)

I suspect that you are probably correct about the lean running settings by the manufacturer. I notice that very time I buy a new B&S engine the emission control regulations in California seem to have been further tightened up a notch or two.
Hope that answers your questions.
Regards,
mustang

Thanks mustang. The main question related to the foam pre-filter. Honda's foam pre-filters are supposed to be oiled, because they have pretty much no effect otherwise, but I have the impression some Honda service places do not oil pre-filters. If the pre-filter is oiled on a Honda, the paper element very rarely gathers any dirt - I regard it as there mostly to deal with the situation if the pre-filter is not oiled or is out of position.

I see from the owner manual B&S recommends that their pre-filter is used dry, which seems a bit odd, but presumably they know what they are doing.