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Bolens Husky 750 oil leak


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#1 dtsh OFFLINE  

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Posted April 28, 2016 - 10:09 PM

I have a 750 with a B&S 7HP (170401) which leaks oil. Initially it had been leaking from around the breather assembly; which the PO  removed for access, but didn't put a new gasket in. I fixed that only to discover that there's another leak, which appears to be near the oil filler tube/plug, so I'm guessing the crankcase gasket is leaking.

 

I have close to zero experience with small engines, but I can read, visualize the problem, and typically can follow directions so I think this should be within my ability to do and thus a chance to learn. By reading the "Illustrated Parts List for Model Series 170400 to 170466" I think I've found the parts I need, the oil seal (29843) and the crankcase gasket, of which there are several thicknesses. What thickness gasket do I need, the list a 0.005, 1/16", and 0.009?

 

While I have it open, is there any other maintenance I should be doing or other parts I should be replacing? The engine otherwise appears to run well and starts easily.

 

I have a few other parts I am looking for as well, such as the drive bearing (1800418) as well, so comments from  vendors or members with spares would be appreciated.

 

Lastly, the engine runs louder than I would prefer and keeping it stock isn't a huge concern as a PO has made a number of other modifications. Is there a different muffler or stack which can be added to reduce the noise levels?


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#2 boyscout862 ONLINE  

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Posted April 28, 2016 - 11:54 PM

Welcome to GTT. I'll be back in a few minutes with a link for you. Try this http://gardentractor...e-seminar-2001/  and the Repairman's Manual from our Manuals Section. Good Luck, Rick


Edited by boyscout862, April 29, 2016 - 12:29 AM.

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#3 WrenchinOnIt OFFLINE  

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Posted April 29, 2016 - 06:35 AM

Hello and welcome , check with our site sponsors a lot of parts a lot of knowledge, Bolens 1000 ( the Doctor) up in the sponsor section will be along shortly, my guess if parts are available , he'll be able to fix you up. I'm a stock guy if I can, but if you want a stack PM Jim Kemp here, he makes a very nice ,one you can check out pics of it under the Garden Tractor heading and this post : MF 12 with Jim Kemps " Winning Trophy Chrome Tip Stack"
Started by WrenchinOnIt, Apr 02, 2016 11:22 AM

Edited by WrenchinOnIt, April 29, 2016 - 06:43 AM.

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#4 Bolens 1000 ONLINE  

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Posted April 29, 2016 - 07:05 AM

Hello welcome to GTT :wave:

 

All the B&S parts are still available and I can help with those items, just send me a private message when your ready, Can you post some pictures of the tractor and engine and post where you think the oil is leaking that will help determine exactly what you need.

 

The mufflers on these were pretty quite in my opinion maybe a baffle inside yours is rotted out.

 

Its definitely nice to see another guy trying to keep these machines original :thumbs: 


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#5 crittersf1 ONLINE  

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Posted April 29, 2016 - 07:28 AM

:welcometogttalk: :camera:


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#6 Bruce Dorsi ONLINE  

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Posted April 29, 2016 - 07:40 AM

I have a 750 with a B&S 7HP (170401) which leaks oil. Initially it had been leaking from around the breather assembly; which the PO  removed for access, but didn't put a new gasket in. I fixed that only to discover that there's another leak, which appears to be near the oil filler tube/plug, so I'm guessing the crankcase gasket is leaking.

 

 I think I've found the parts I need, the oil seal (29843) and the crankcase gasket, of which there are several thicknesses. What thickness gasket do I need, the list a 0.005, 1/16", and 0.009?

 

While I have it open, is there any other maintenance I should be doing or other parts I should be replacing? The engine otherwise appears to run well and starts easily.

 

I have a few other parts I am looking for as well, such as the drive bearing (1800418) as well, so comments from  vendors or members with spares would be appreciated.

 

Lastly, the engine runs louder than I would prefer and keeping it stock isn't a huge concern as a PO has made a number of other modifications. Is there a different muffler or stack which can be added to reduce the noise levels?

 

 

Welcome to GTT !

 

I believe the correct part number for the oil seal is 298423. 

 

A # 27750 crankcase gasket is the most commonly used gasket at 1/64" thickness.  .....However, it is possible the bolts holding the crankcase cover have loosened over time.  ...You may want to check them before removing the engine, to save some unnecessary work.

 

Sometimes the plastic oil filler plug (#66768) would crack and cause a leak. 


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#7 blackjackjakexxix ONLINE  

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Posted April 29, 2016 - 09:13 AM

Welcome aboard,we love pics here


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#8 sodisr OFFLINE  

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Posted April 29, 2016 - 09:54 AM

Welcome Wisconsinite..   :wave:    !!!!



#9 dtsh OFFLINE  

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Posted April 29, 2016 - 05:03 PM

Welcome to GTT. I'll be back in a few minutes with a link for you. Try this http://gardentractor...e-seminar-2001/  and the Repairman's Manual from our Manuals Section. Good Luck, Rick

 

Thanks, I had missed the Repairman's manual, it looks to be what I was looking for.

 

 

Hello welcome to GTT :wave:

 

All the B&S parts are still available and I can help with those items, just send me a private message when your ready, Can you post some pictures of the tractor and engine and post where you think the oil is leaking that will help determine exactly what you need.

 

The mufflers on these were pretty quite in my opinion maybe a baffle inside yours is rotted out.

 

Its definitely nice to see another guy trying to keep these machines original :thumbs:

 

 

170401_engine.jpg

The area it appears to be leaking at is circled in red.

 

 

Welcome to GTT !

 

I believe the correct part number for the oil seal is 298423. 

 

A # 27750 crankcase gasket is the most commonly used gasket at 1/64" thickness.  .....However, it is possible the bolts holding the crankcase cover have loosened over time.  ...You may want to check them before removing the engine, to save some unnecessary work.

 

Sometimes the plastic oil filler plug (#66768) would crack and cause a leak. 

 

Thanks, I checked the bolts and they appear to be snug and the oil plug appears to be intact, drat.

 

 

For those that asked for it, here's a pic of the tractor. It's not pretty, but it should do the tasks which I bought it for, which is what is important to me. I also have several attachments, snowcaster, tiller, 32 deck, and a plow. I doubt the deck will see much use, but the rest were the driving factors in the purchase. The snowcaster needs to be cleaned up, repaired, and repainted before winter, but the rest look to be in fairly good shape.

750.jpg

 

The zero turn mower in the background also leaks oil and the plan is to pull the engine and see where it's leaking this fall after it's no longer needed. The engine in that one is a Kohler Magnum 18.


Edited by dtsh, April 29, 2016 - 05:15 PM.

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#10 Bolens 1000 ONLINE  

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Posted April 29, 2016 - 05:07 PM

Not a bad looking machine , if its leaking where that circle is I would suspect the gasket 

 

The only other possible spot in that location excluding the oil cap is that governor to the right but it looks dry in the pic.


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#11 dtsh OFFLINE  

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Posted July 13, 2016 - 01:17 AM

It's finally time to fix this.......

 

I figured while I've got the engine out and split open, I might as well do some more work. Cleaned the head and have the carb torn apart and cleaned. I have to admit, it looks much better than I was expecting.

 

I meant to take some pics of the cylinder wall, but apparently I didn't. I was expecting some serious horrorshow here as I've never looked inside one of these aluminum cylinders and I expected to see scoring and chasms. To my surprise, I saw a nice, smooth cylinder, without any discernible marks.

 

Here's a pic of the head before and after some cleanup

750-head-before.jpg

750-head.jpg

 

And the crankcase

750-crankcase.jpg

 

The only issue I had was removing the exhaust valve. The repair manual I have apparently pre-dates this retainer design and it took me quite a bit of searching the internet and poking at it to figure out how to get it apart. The disk portion of the retaining clip can lift up, releasing the two shims (easier said than done). This is going to be so much fun putting back together. Any advice from the pros?

750-exhaust-valve.jpg

 

On the plus side, I think I'm about ready to order replacement parts. While the 750 is down, I'm going to look into a few other issues as well. The main drive bearing makes a racket when it's spinning and the PTO could use some attention. Figure I might as well clean it up, perhaps put some paint on it, and find out what the issue is with the charging circuit while I'm at it.

 

The issue with the generator is that it will start, but it doesn't charge. I am unsure if it's the generator, the regulator, or something else. I need to learn a bit more on the system and see what I can find. Thankfully it almost always starts with one pull...or at least did before I took it apart.


Edited by dtsh, July 13, 2016 - 01:20 AM.

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#12 Bolens 1000 ONLINE  

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Posted July 13, 2016 - 07:06 AM

Looks like your making some progress



#13 29 Chev ONLINE  

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Posted July 13, 2016 - 08:43 AM

"The only issue I had was removing the exhaust valve. The repair manual I have apparently pre-dates this retainer design and it took me quite a bit of searching the internet and poking at it to figure out how to get it apart. The disk portion of the retaining clip can lift up, releasing the two shims (easier said than done). This is going to be so much fun putting back together. Any advice from the pros?"

 

Buy, borrow or make a valve spring compressor tool similar to this one to compress the valve spring - https://www.amazon.c...r/dp/B000P0VTG4  .  Once the valve spring with the valve spring cap is compressed you can set the two halves of the valve keeper in the grooves using a magnet - once in the groove use a small flat screwdriver to hold the keeper on the valve while you pull the magnet away.  A little bit of Vaseline on the valve where the groove is will help to hold the keeper in position while you release the valve or a small O-Ring slid over the top of the keepers will secure them as well - make sure you keep the O-Ring up near the top of the valve stem so that it does not become trapped in the valve spring cap and then once the cap and spring is released remove the O-Ring. 


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#14 Bolens 1000 ONLINE  

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Posted July 13, 2016 - 09:25 AM

Your best friend will be a valve  spring compressor and , then use a screw driver or small maget to install the keepers, as mentioned above a dab of vasoline or grease will keep the halves on the stem.

 

http://bolenspartsan...ecumseh-kohler/

 

 

While the valves are out I'd lap them as well



#15 MailmAn OFFLINE  

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Posted July 13, 2016 - 09:26 AM

Wow, good for you tearing into this engine.  I give you a lot of credit.  I still haven't managed to tear open any of my Wisconsin engines yet (even though the engine on my 850 REALLY needs to be rebuilt to get it running again as it sounds like it has a major vacuum leak somewhere in it and it doesn't have any compression or power anymore, even though the engine will still "run".)  The top of that piston and those valves, especially the exhaust valve, were certainly carboned up pretty badly, huh?  Nice job cleaning those up.  I'm sure that will help it run better when it is all put together.

 

I see you also pulled the valves out, so are you planning on getting some valve lapping compound and grinding and re-seating the valves in the head?  Are you planning on replacing the valves, seats, and retainers or keeping the original ones?  If they don't look that bad, there is probably no reason to replace them unless one of them is bent somehow.  I'm also assuming from your earlier posts that you're planning on putting some new crank bearings in the engine as well?  I'm sure that will help it run more smoothly and quietly.

 

As for the engine noise, I'm also in the camp that the stock muffler is probably rotted out inside and that is why it is so loud.  Buy a new muffler for it (they are pretty cheap and should only run you $10-$15 at most) and try that first.  Chances are it should quiet it down some.

 

Good luck with it and keep us updated on your progress!  It looks like you're doing really good so far.






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