newbie would appreciate help

[kentrx1]

bought a 154 about a year ago, running, but with no power at all. would barely pull itself, but no smoke at all even after running for 30 plus minutes. have tried a few things like carb adjustment, governor adjustment, soak with seafoam, and got no improvement. did a compression test today with throttle wide open and all plugs removed. from front of engine going back the first plug had 110 compression, middle two cylinders around 25 each, and back cylinder had 120. I am thinking a valve issue or blown head gasket. My plan is to pull head next. i have the manual, but would appreciate tips on how to proceed. i plan on this being an occassional use mower, as it has the swing blades and i wish to keep some weeds knocked down in the woods----but nothing heavy or thick but might hit a root every now and then. will not be used a lot so i would like to make it usable, but not trying to make it brand new.

[Eugene]

Adjust the valve tappet clearance before going any further.

[kentrx1]

Thanks. Will check that

[outdoors4evr]

The middle two cylinders do not have enough compression to contribute to the power. Eugene is leading you toward the issue, but I'll be blunt. The valves in the cylinder 2 & 3 are not closing or sealing. You may be able to free these up through the valve cover or by removing the head and the valves to clean up the valve seats.

[Eugene]

You may be able to free these up through the valve cover or by removing the head and the valves to clean up the valve seats.

You more than likely have stuck valves. Before you remove the engine head, remove the hood and spark plugs.

You can see the edge of the valves through the spark plug hole. Spray solvent under the valve heads. Gently tap the stuck valve down. Rotate the engine over until the valve is stuck up. Repeat the process until the valves are free.

Spark plugs in place, operate the engine for some time, several hours. Then check the compression again, this time dry then wet tests.

[Jim Becker]

Note:
- Compression on 1 and 4 is good.
- Compression on 2 and 3 (adjacent cylinders) is identical, low, and NON_ZERO.

My bet is the valves are moving (otherwise compression would be zero). A blown head gasket between cylinders 2 and 3 causes them to have identical compression.

Yes, finish checking the valves first as it can be done without pulling the head off. But when servicing the valves doesn't fix it, pull the head and look at the head gasket. Be sure to drain the coolant before pulling the head. Once removed, check both the head and the top surface of the block for flatness. When you reassemble, put sealer (like Teflon paste pipe sealer) on all head bolt threads.

[BigBill]

Before doing anything I’d put seafoam in the gas tank and crankcase oil. It will free and reseat stuck rings and sticky valves. Try it first.

[kentrx1]

Note:
- Compression on 1 and 4 is good.
- Compression on 2 and 3 (adjacent cylinders) is identical, low, and NON_ZERO.

My bet is the valves are moving (otherwise compression would be zero). A blown head gasket between cylinders 2 and 3 causes them to have identical compression.

Yes, finish checking the valves first as it can be done without pulling the head off. But when servicing the valves doesn't fix it, pull the head and look at the head gasket. Be sure to drain the coolant before pulling the head. Once removed, check both the head and the top surface of the block for flatness. When you
reassemble, put sealer (like Teflon paste pipe sealer) on all head bolt threads.

Head removed, all valves moving freely, no obvious damage Don’t see obvious blown gasket either, but must admit not sure what I am looking for. There were no symptoms of coolant getting in cylinders before teardown. I realize between cylinders 2 and 3 highly likely something is blown but would feel
better if visible flaw. I tried to post picture but tells me file too large. Possible cylinder head has a slight dip in middle of head. Any problem having these heads surfaced?

[mozer71]

If the head needs resurface, precision straight edges can measure that. I thought it was classic flat head gasket leak between #2 and #3. Stuck valves was good and maybe a broken spring or two. Since you didn't see any water penetrating into the oil (or oil into the coolant) and nothing across the head gasket, Look close at the block and head for evidence. Something which happened before at #2 and #3.

[Stanton]

...I tried to post picture but tells me file too large...

Here's some info on posting pictures:

• How to Upload Pictures to a Post
• Forum Picture Posting And Other Interesting Things You Can Do

Pictures have to be 500KB or less. Load them on your computer, downsize them with Paint or other resizing software, then post them as attachments. See the "Attachments" tab at the bottom of your posting page.

[kentrx1]

[mozer71]

Gosh these are good pictures. I'm still studying the first one but see definite issues. Thanks. This is going to be fun because all these knowledge guys are going to notice things we never even thought of.

[kentrx1]

I look forward to the education!

[Slim140]

Looks like your #2 and #3 valves have bad pitting around them. Wonder what the valve face and seat looks like?

[kentrx1]

Short of pulling engine and carrying to machine shop, what do you suggest doing to top of block and valves? Just trying to have occasional use mower. Not a major restoration. Much chance of surfacing head, putting back together and getting some hours of use out of it?