Plugged exhaust ports and or muffler.

Walt Conner

motherLODE

Anyway, Walt knows his LBs and probably has it right. The 10304 has the 'V' (value) engine which if it has used LB oil for many years is almost certain to have clogged exhaust ports. Read up on cleaning these before attacking them with metal tools - you will scratch the piston. While you have the muffler cover and baffle off, tighten up the bolts under the baffle that hold the muffler plate to the engine. Check the steel muffler cover for cracks/holes and fit. Lightly tap from the inside to flatten out the bolt hole areas for a tight fit. You've already learned to try the air vane to see if the engine will pick up. The throttle plate in the carb is attached to the vane shaft. At the base of the shaft on top of the carb is a knurled collar that is the governed speed adjustment. You use this to adjust the top engine speed once it's running right. This same arrangement was used on all 'V' and 'E' (Duraforce) engines.

Thanks Walt and Saxman the exhause ports was the answere. 2 holes were plug 90% the last hole as 30%. Cleaned them out and now I have alot more rpms. I also have a question on the 680540. It has almost no compression what so ever. I looked at he reeds and they look good. The rings must be shot. Is it an easy task to put in new rings? This lawnboy is a beast and in extremely good shape so I dont want to trash it.

'F' engine, probably the most sucessful one they made. Like all LBs, it will have an iron cylinder sleeve. Mr. Conner can tell you all about doing a ring job. Short blocks still come up on ebay and most if not all parts are still available because they made so many mowers with this basic engine. It could be possible that the crank seals are bad. The 2-cycle requires a sealed crankcase to function, and the seals have to hold vacuum and pressure. The rings may also be stuck and not expanding. You'll just have to check it out and see what's happening with it.

HMMMPH!! I let one sit last night on my old lawn mower search! Didn't even get out to look at it! And, i gave one away last week-didn't even ask for monet for it. I almost kissed the guy for taking it, and no, I'm not THAT way!

Rings are cheap, easy and readily available. Did you check the compression with an actual gauge? Reeds and crank seals will not affect the compression to a point where you could tell by pulling the rope by hand. If compression is low on a gauge at the spark plug hole, your have a ring/cylinder problem.

I was checking the compression on the plug side. I stuck my finger over the hole and pulled the rope and it has very little compression. I am pretty sure its rings. Here is a list of the other mowers that was given to me...5273, 10323, 10515, 10415 and a regular 4 cycle mower. I will keep everyone posted as I figure things out...

My point was, if you have low compression, it's not caused by the reeds or crankseals.

'My point was, if you have low compression, it's not caused by the reeds or crankseals'

I thought your point was very clear the first time. My point is more air is drawn into the crankcase and then pushed into the cylinder, resulting in higher compression than the 'static' compression, when the seals are good. Case in point, the engine won't run without those seals. I agree that in this case something more is wrong than just the seals.

Zoomie; you got a 10323? That is one sweet machine. 6.5 HP Duraforce, lightweight steel deck, Variable Speed RWD. That is one mower I should have kept.

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Yep Sax without Base Compression it's a No Go ! Zoomie , a Mother Load is Right , sounds like a interesting score for both parties . I almost spilled the Cereal Rusty on the Kissin Issue Bro lol ! :)

Yes, they can be a handful, but I have to admit I miss that outboard sound and smell. 4-cycles are so boring. But its a boring that comes with reliability.

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I have a 10515 that runs good but the throttle cable broke. Can I get just the cable and not the assembly? I did a parts look up but all it says is throttle control.

Zoomie; you have to use a html link for pictures.

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The ones that I have finished and the two that are getting parts canned from. Hate to do it but parts are expensive!!

Where's the 10323?

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Eight non-working lawnboys and he hates to work on them! I think there is a message there.....

He might just be set in his ways but he is a good fellow...Just out of curiosity what do you think these mowers are worth? I dont have room or use for these extra mowers...

Not worth much imho. But check closed auctions on Ebay for the ending price.

The 10323 might bring $150 running and cleaned up. The 10304 about $100. The older ones might be more, but you most likely would have to ebay them and be willing to box them up, transport to UPS, etc. You could part them out but it would be quite an undertaking.

"My point is more air is drawn into the crankcase and then pushed into the cylinder, resulting in higher compression than the 'static' compression, when the seals are good. Case in point, the engine won't run without those seals."

I agree with the first part to a point, except that I've never seen anyone take compression readings while a single cylinder mower is running. You will never see the compression difference at the low RPMs you have by pulling the motor over by hand.

As for the last part, I have had 2 Lawnboys in the last to years that ran fine with the lower seals completely blown out. They had not governor response and would die under heavy load but otherwise, ran just fine.

I have a 10515 that runs good but the throttle cable broke. Can I get just the cable and not the assembly? I did a parts look up but all it says is throttle control. Kinda pricy!

Lawnboy/Toro Cables are pricey. The cable is 92-1633 and is $36 from mowpart.com.

Hey orangedot; you're fulla chit.

Sorry you can't accept the facts. Compression is developed by the piston rings passing the ports and shutting off leakage and starting the compression of the air trapped above the rings. It makes NO difference if you have crank seals or not, they do NOT come into play at the low RPM that people use to check compression at the spark plug by pulling the rope. A standard compression test will NOT tell you if you have a crank seal problem in a 2 cycle Lawnboy.

As for running without the lower seal? This has happened many times, not normally, but it happens. Check some other forums, others will tell you they have experienced the same thing.

I respect your knowledge and experience, but on this, you're wrong. Neither are absolutes.

odf, You're right on both points.