OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Tech Talk SB Model 45 - Clutch and Engine Problems

Hi,

My first attempt at fixing my SB 450589, which would appear to need a new clutch. Any tips and info would be appreciated as I am not a mechanic but happy enough to follow instructions. I looked for a manual on the website but couldn't find one.

Stuart R

Hi Stuart, welcome to Outdoorking. Deejay is the man for this project, but he is not present right now. To get the show on the road, could you post pictures of your machine please, including its model identification plate, plus pictures of its clutch, and a description of what is wrong with it. It may be fixable with less radical surgery than a new clutch, but this depends on what it is doing, and exactly which SB45 variant it is.

Deejay will probably commence his involvement by splitting your project off as a separate thread, but I'll leave him to make that decision.

Thanks for replying, The mower is a model 450589. Despite having a very good reel (replaced 12 months ago), the mower was 'grabbing' and making a grinding sound when cutting all but the shortest grass. The reel would stop rotating and then, when I raised it off the grass, it would start spinning again. I have a couch (Queensland Blue) lawn that is not thatched so I took it to the local shop for a quote to be fixed. That came back in the vicinity of 1K, so that was out of the budget. 4 Pics attached as requested.

Stuart

I can't see any pictures, so something seems to have gone wrong there. Could you try again please?

At the moment it sounds rather more like reel bearing failure or maladjusted reel than clutch failure. When it is exhibiting this "grabbing", if you quickly stop the engine, pull off the spark plug lead, and try to turn the reel by hand, does it spin smoothly and freely? REMEMBER: NEVER PUT YOUR HAND NEAR THE REEL WITH THE ENGINE RUNNING, UNDER ANY CIRCUMSTANCES.

Hi Stuart R, and a warm welcome to the forum. It's great to have another SB Model 45 owner on board.

Stuart, grumpy has given you good advice there re your safety....also his diagnosis may prove correct. However, this could prove to be a clutch problem or a combination of both.
As grumpy has explained, we need the pics he has suggested taking so we can ascertain what is happening plus some good pics of the cylinder reel, bottom blade and the reel adjusters on both sides; I can then step you through the repair process.
I will need you also to remove the chain cover and take some pics of the sprockets and chains...particularly the sprockets where they are not covered by the chain...this will let me see their condition.
Please use the OutdoorKing inline uploader; for instructions please click HERE
Please do NOT operate the machine until we identify the prob....it will only cause more damage.
Once again Stuart, to OutdoorKing.

Sorry about the pics, Still getting used to the website. i will try your suggestions and get back.

Thanks Deejay, I will get the photos to you asap.

No probs Stuart, it takes a while to navigate around here, you doing well mate. Well from the pics I can tell that it is the later model Scotty....and that it needs a little TLC.
But with patience and some general maintenance, I think she will come up a treat!

Hi, some more pics for you. I cant test the engine stopping you mentioned as it wont turn over at the moment, which is surprising as it normally is not a problem. Maybe the guy who looked at it did something. I will try a new spark plug. With the clutch handle upright the reel spins freely

Hi Stuart, thanks for posting the pics....

What I propose to do here is tackle your problems in 2 parts.
The first part will be to get the prob with clutch and cylinder reel adjustment and chain tension corrected. To do this (and considering the good condition of the sprockets,) I believe the reel bearings may be shot, causing the snatching/grabbing you describe

The second part will be to hand you over to Grumpy (our Briggs guru) to get the engine sorted and running sweetly.

What I need you to do is:
(1) Remove the cylinder reel following the instructions contained HERE You don't have to remove the soleplate, we just want to make sure the reel bearings are serviceable. If in any doubt....replace them....(I would anyway, so I then know their history )

(2) Re-install the reel and adjust the cylinder reel to bedknife (bottom blade) clearance correctly. You will find the instructions for doing this is contained HERE
Once that has been completed, can you please let us know and we will proceed on to the clutch adjustment.
Just be patient and proceed carefully...any questions, please post to this thread. Best of luck!

Thanks, I will go slowly as I have been inspired by the other examples on the site to repaint the body. I have a few weeks off so I will start on your instructions and get back to you with progress reports.

Thanks for the reply, Stuart.
Just remember, we are here to help as you go along....any questions, please post to this thread....and we will give you the advice you require.
Best of luck with it...you will be fine!

Back again. I have dismantled the clutch and remover the engine from the body, ready for painting. Some photos for you. How do I remove the bearing from the end of the reel and are there any special paints that I should be using.

Thanks again, learning heaps, Stu.

That reel looks as though its never been ground since New. Go to local auto shop the bearings are dirt cheap, I used kill rust enamel paint on my reel.

Hi Stuart, sorry for the delay in getting back to you, I have had a very busy weekend.
For the painting of your engine, you would find that an automotive engine enamel would be best; because it is designed to take the heat.
For my cylinder reel, I had mine powder-coated in fire-engine red, but as Jason said Killrust would also be fine.

To remove the bearing, you will need a 3 leg gear puller, which are not expensive and available at most Auto shops or good hardware stores.

Thanks. looking at the clutch and the cork, will this need replacing? I will also need a new gasket where I took the engine apart. Is there a special name for this gasket?
Stu

Hi, I have had the bottom blade sharpened, the reel ground and replaced the reel bearings and the clutch cork. I have also put a new spark plug, air filter and oil in. Before I put everything back together, I have tried to get the motor to turn over but with no luck. The pull cord does not pull freely and everything feels really stiff inside the motor. Where do I go from here?

Thanks
Stuart.

Hi Stuart, Re: your Briggs problem, I will hand you over to grumpy. our Briggs and Stratton guru, who will help you sort the engine probs....

Hi Stuart, I need to get some background on how the engine became stiff to rotate. I see from one of the pictures that you have removed the crankcase cover. Was the engine stiff before you did that?

If it rotated freely before you worked on it, we will need to go over the steps in the work you did on it. If it was already stiff to rotate before you laid a spanner on it, we would proceed in a different way.

Is the oil sump filled to the correct level with SAE30 oil?

The engine wasn't stiff before I removed the crankcase cover, but I still couldn't get it to start. I have filled the sump to the bottom of the fill holes with SAE 30. After removing the cover the larger of the cogs came out and the two tappets (??) fell out. I put them back and then replaced the larger cog into what I thought was the original position.

We may have a few problems there Stuart. I think the first thing you need to do is to remove the engine from the mower, and see if it is still stiff. If the problem is just an alignment one, the engine may be free to rotate once it is removed from the mower. If it is still tight, it is going to be necessary to remove the crankcase cover again and reassemble the engine step by step. Please do not try to start the engine until we get this resolved.

To align the camshaft and crankshaft correctly you need to align these two circled dots,

Sorry the keyboard had a fit half post there, also I am hoping there is no damage to the crank bearings in the cover from leaving the key in the crankshaft, memory says it should fit past but may not...

The camshaft timing seems to be right by a simple tooth count.

The key may have wounded the crankshaft oil seal as well as the main bearing, plus I don't know what the final status of the crankcase cover gasket will have been after removal and re-installation. Also, if the tappets happen to have been put back into the opposite positions (intake and exhaust interchanged) the tappet clearances may be quite a way out.

I'm not confident yet about whether there is end thrust on the crankshaft due to the clutch cotter pin adjustment, which is why I've asked for the engine to be removed.

Once we work through these points, hopefully all will be well - but I don't yet know the cause of the rotational stiffness, unless it is end thrust on the crankshaft.

Stuart, this may appear to be a stupid question, but why did you disassemble the crank case cover?

In that pic the timing seems out by one tooth would that be enough for a valve to just hit and make it hard to turn over?

The valves cannot hit the cylinder head in that engine due to incorrect timing, Chris, I do not think that is the problem. (It is sometimes very different though, on some OHV or OHC engines, when the valves can hit the piston with devastating results. That is why it is a good idea to replace the rubber cam drive belt in certain car engines at the recommended intervals.) However if the camshaft timing is out by one tooth, the engine would run badly if at all.

Grumpy, I have taken off the cover again and removed the larger of the cogs. The pull cord now moves quite freely so it must be something wrong with the alignment when I place the big cog back in. Your thoughts (and remedy!)

To time it the timing marks should look like this...grumpy will tell you the best way of aligning up the timing marks.In that pick its one tooth out....

Stuart, the first step is to rotate the crankshaft (which has the small gear on it) until the dot on the gear is at the closest point to the camshaft gear. Lift the camshaft gear (the big one) out of mesh with the small gear, and rotate it until the dot on the gear is in line with the dot on the crankshaft gear. Then slide the camshaft gear into mesh with the crankshaft gear so the two dots are close together, as in Chris' drawing. Remember the gears have helical teeth, so the camshaft will rotate as you slide it into place. You choose the right point and slide the gear into place. If the dots are not perfectly aligned, slide it back out, rotate it one tooth, and try again until the dots are matched.

The because the engine is only tight when you have the crankcase cover installed, it appears that installing the cover jams something, probably either the crankshaft or camshaft. Can you post a picture of the black gasket that goes in between the crankcase cover and the crankcase, please. That gasket is 0.015" thick, and the axial clearance of the crankshaft is only 0.008" maximum, so if you have left out the gasket, the crankshaft will be squeezed endways when you tighten up the screws that hold the crankcase cover, and the crankshaft will not be able to rotate freely.