OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Tech Talk GV150 tuneup help needed

Grumpy, waiting on parts from usa .this includes top bearing and two new top seals lol.engine has been stripped down ready for new parts and reassemble, in the meantime I'm going to make a tool from poly on the lathe just like the one in the picture .I will let you know as soon as I'm finished assembling and tested.Thanks again .

Thanks for the update - I'd like to see pictures of your polyethylene press tool before, during, and after, because I'd have used steel. It should take well under a ton to push the bearing in, and even less for the seal, but my limited experience with plastic press tools has been very unsatisfactory. My explanation is that their extremely low Young's Modulus results in a lot of distortion under load, so they don't push things in straight. The tiniest difference in load from one side to the other, results in allowing the sticking spot to lag behind, and then you're pushing the thing in crooked. Force required immediately rises very high, and the press tool distorts more. The outcome is a press tool that looks as if it has melted, and a botched job - perhaps even a damaged housing.

Hi Grumpy.Thanks for that .I will use a steel tool . I'm only a backyarder .The poly tool I made today was made out of a skateboard wheel which is a bit too soft for this job. Makes total sense what you have said. The model I am working on is /GV 150-3157301 purs like a kitten - roars like a lion when you want it to untill oil seaps into the points. The oil seal in the motor which is what the mower shop sold me is a 41-25-6 unlike the one in the picture which is a 41-21-6 so I hope I have ordered the right one this time .The seal I used last time seemed to go in quite easy and the mower shop told me to push in as far as it would go but didn't look right. It sat in about 5+ mm and the diagram shows 2mm.I've fixed a lot of different engines and have always replaced with new seals top and bottom and never had a problem like this one. As for uploading photos I will when I learn how to.I barely know how to get to this page.I'm hopeing to get one of the kids to show me how to use the forum properly one day.please have patients I will learn .once again thankyou very much and I hope I havnt confused you any with what I have written because I think its confused me.

There is no problem, roebuck, you are getting the job done, and learning without breaking anything or hurting anyone.

An oil seal is usually described by three dimensions: interior diameter, exterior diameter, and width. Honda says the top crankshaft seal is 21x41x6. That means they think they made the crankshaft to fit a top oil seal with an interior diameter of 21 mm. It would appear that you have been sold 25 mm oil seals up to now, so the diameter of the sealing lip was 4 mm larger than the shaft it runs on. Because that engine has a pressure lubrication system, and one of its purposes is to lubricate the ballrace at the top of the crankshaft, having effectively no oil seal behind that ballrace would inevitably result in rather a lot of oil ending up on your breaker points. Up to now I'd been wondering how you were getting as much oil as you reported - even a sick and sorry oil seal would only ooze a bit, and you were talking about a lot more oil than that. Now it all becomes clear.

Just for interest, here is the assembly diagram for the crankshaft:

As you can see, the oil seal goes in from the top of the crankcase casting, and the ballrace goes in from underneath. The crankshaft must have a step-up in diameter just behind where the oil seal runs on it, because its ballrace is a 6205, which has an internal diameter of 25 mm and an external diameter of 52 mm.

Post edit: As will become clear later in this thread, the Honda workshop manual turns out to be incorrect. The correct seal for this engine is 25x41x6.

With regard to posting pictures, if you look at the box you type your post in, right above it is a row of colourful icons. The fifth one from the left looks rather like a paint spray can with a blue upward arrow in the top right corner - I've circled it in red here:


If you select that icon, you will see this:


Stab the browse button, and you will see whatever file directory in your computer you looked at last. Navigate to where you put the pictures you want to upload, and double-click the first one. Its location will then appear to the left of the browse button. Jab the "Add file from your PC" button. There will be a little animated picture with red diagonals sliding across it for a while, then a thumbnail of the picture will appear in the top left corner of the box. Punch the "All done" button on the bottom right. You will then be back in the typing box, posting your message.

Hi grumpy,plastic tool I made and can you tell me what is the metal tool is for .I picked the tool up on ebay a while ago along with some other mower nicknacks ,I asked the fellow what it was for but he didn't know . As for the seal are you saying i need to order a smaller inside diameter if so I'm sure the mower fella told me I can't get the original so he gave me one that replaces it and same when I ordered from usa.sorry but I'm a little confused . Is it possible to still order 21-41-6 oil seal ? Thanks for the guide to upoading photos.your a great help .

I can't identify that device. It looks as if it is a press tool, probably for installing a seal or bearing (or maybe one of each), but I have no idea what its specific application was.

To move forward with this top seal problem, I suggest you measure the diameter of the crankshaft, where the oil seal runs on it. If you look at the diagram from the parts list, you can see a parallel section (circled in red) just below the flywheel taper, then a step up to the larger diameter for the inner ring of the ball race:


According to the engine repair manual, the oil seal diameter (circled in red) should be 21 mm, and the ball race diameter right below it, should be 25 mm. If you confirm those diameters, we will know that the workshop manual refers to the engine you have. I can't see how it can be otherwise: your serial number fits for a GV150 K1 (that is, not an early production GV150) but let's just make sure we are all talking about the same engine. So far I have never known a Honda workshop manual to talk nonsense, but we all have new experiences every day.

Here are the production records for the GV150. As you can see, they were all made in Japan:


The reason I want to be very sure about this, is that the Honda spare parts list seems to only show a 25x41x6 oil seal (part number 91201-Z0T-801). This would be the right size to fit on the same diameter part of the crankshaft as the ball race. So, we need to confirm that your crankshaft is like the one in the diagram I've shown in this post, with a step down in diameter from 25 mm where the ball race fits on it, to 21 mm where the oil seal runs on it.

The parts list and the manual could both be correct if there had been a running change in the engine design, making the crankshaft diameter a constant 25 mm, and deleting the step down to 21 mm shown in the workshop manual. Workshop manuals are often not updated when that kind of thing happens. The problem we have is that if your engine is the original 21 mm version, it may be difficult to get an oil seal for it. 21x41x6 is not a standard size for oil seals.

Of course one possibility here is that someone in Honda's Department of Cost Saving Ideas That Only Screw Up the Product a Little Bit, found that the recess in the top of the crankcase casting that the oil seal presses into, was just about deep enough for the oil seal's lip to reach onto the 25 mm diameter part of the crankshaft. They could then substitute the 25x41x6 seal for the original 21x41x6 seal, and warn their dealers to be sure and always press the seals in as deeply as possible, because if they didn't, the points compartment would fill with oil and the engine would stop.

Please come back to us with a picture of the top part of the crankshaft, and those two diameters.

I hope this is what you have asked for. I'm not good on terminology but in the diagram you sent it has a part number 8 a chain and mine does not have this chain if that matters or not. Thanks again .

First, the easy bit. 8 is a timing chain. It runs around a small sprocket on the crankshaft and a large sprocket on the camshaft, so that the camshaft rotates exactly 1 revolution for each 2 revolutions of the crankshaft. This is at the bottom of the crankshaft, close to the large cover that goes across the bottom of the engine. You make a good point, though. Your GV150K1 has timing gears, where the original GV150 had a timing chain. The online parts list is for an early GV150 with a chain.
http://www.ereplacementparts.com/ho...ine-parts-c-37657_37658_38010_38030.html

Now, let's talk about the flywheel end of the crankshaft.

1. In your last picture, is the inner ring of the ball race a good fit on the crankshaft?

2. What is the diameter of the surface in the red circle?



3. Is the surface in the green circle eccentric to the rest of the crankshaft? If it is, it is a cam that operates the breaker points. This is a bit concerning, because Honda's manual shows the cam as being the first parallel surface after the flywheel taper - see red oval:


4. There is a narrow shiny surface inside the yellow circle. Is this where the lip of the oil seal has been touching the crankshaft? What is the exact diameter of the shaft right there?

1The inner ring of the bearing fits snug. 2The red line is 16mm shaft. 3The green is the cam that opens and shuts the points.4 yes I'm pretty sure this is where the lip of the seal has been running . Could you show me with a dot where the oil seal lip is supposed to be.

It appears that the Honda workshop manual is wrong about the correct required size of that seal: it has to be the same size as the shaft, which unfortunately is a bit undersized from 25 mm. Also, I now understand why the counter jockey told you to push it in a long way more than 2 mm below flush: the shaft is tapered, and the further you push it in, the closer the shaft is to the correct size.

The shiny mark, with the yellow oval, appears to be where the seal-lip has been running throughout the engine's life up to now:


Run your fingernail across that shiny mark and look at it closely, to ensure that it is a mark, not a groove. If it is a groove, you need to move the seal 2 mm sideways from that previous position.

Next, I suggest you oil the lip of a good seal then slide it down over the shaft until its lip is right over that shiny mark, and verify that the lip is in firm contact with the shaft, all the way around. Then check that the housing is clean where the outside of the seal will sit in it.

Now, do you know which way around to install the seal? The correct answer is, the same way around that Honda did when they built the engine. In case you don't remember which way that was, please read this carefully:
http://www.sealing.com/fileadmin/docs/Lip_Seal_Installation.pdf

If you are unclear about anything, please say so before you install the seal, since it is difficult to get them out without damage, once they are pressed in.

I've downloaded the file and soon as I have the parts I will read the file again very carefully . Iwill let you know how I go . I very much appreciate all you have done and will follow your instructions .ps who said you are grumpy? Take care.

roebuck, part of the reason I want you to read that oil seal installation paper carefully, is that we still need an explanation for why your two previous seal installations leaked badly. I'm concerned that you may have put the seals in backwards. Here is the lubricant flow diagram from the workshop manual:


In what seems a rather bold design decision, Honda has elected to direct the full output from a Hobourn-Eaton (trochoidal) oil pump up through the hollow camshaft, into the space between the ballrace and the top oil seal, under pressure. From there it trickles and splashes down to lubricate the remainder of the engine. This means the top seal is actually under pressure from inside the crankcase. It can only restrain the oil from actually pumping out of the top of the engine in quantity, if the oil seal is pressure-tight.

Here is a typical double-lip, spring-loaded oil seal, which may be similar to the one Honda uses:



The red oval shows the "dirt lip" side of the seal. This side must be on the outside, not the pressure side, of the seal. Its only function is to keep crud from getting close to the "real" lip and wearing it out. If pressure is applied to the dirt lip side of the seal, it will simply lift the real lip out of contact with the shaft.

The green arrow shows the side of the seal that must face toward the source of oil, and pressure. The more pressure is applied, the more tightly the seal will seal. This pressure side of the seal must face toward the ballrace.

This is the way I would have pressed it in . The next picture I wouldn't of pressed it in.
More pics of the bearing housing and oil passage . Hope that's what you mean.
Another picture of the seal the right way up on the shaft . The seal you see is from another engine so ignore the size only for demo.
Is this what asking. Cheers.

The open side of the oil seal must face toward the ballrace. The closed side should face upward, toward the breaker points. As far as I can tell, that is the way you have shown it in the pictures, so we still don't have an explanation of why it leaked.

Hi Grumpy,I've received the new seals for hond gv 150 . The one from USA are redish they where bought by engine number . The black seal I bought from local honda shop as a replacement. The redish one is slightly higher on the outside wall.
The redish ones are left and right the black is middle ,does this make much difference. The bearing arrived as well and it was ordered the same way from USA by engine number as a replacement . It appears to be slightly thinner around the ball race which may take a bit of pressure off the seal maybe.
What do you think

First, in this application the thickness of the seal probably has no effect, as long as the position of the sealing lip is the same distance from the engine side of the seal (not the breaker points side). If that distance is not the same, the sealing lip may not run in the old position (the worn, polished circle around the shaft), which is not important anyway as long as the shaft is smooth, and the polished circle is not worn down to a smaller diameter. (Since the shaft is less than the seal's nominal diameter of 25 mm anyway, you would not want to make the situation worse by running the lip on a worn-down spot on the shaft.)

The picture of the ball races does not show the brand of the new one. Because it is marked 6205/P6, I think it is probably SKF brand, because P6 is a specific SKF tolerance class. The old bearing was NTN brand. They are both reputable brands, and they are both 6205 open bearings. The minor variations in features between manufacturers are not something to be concerned about. The important thing is whether the old one has any more slack in it than the new one. If you can reduce the slack (amount the outer ring can move radially or axially when you hold the inner ring in a fixed position) by replacing the bearing, that will make life easier for the oil seal.

The first important test is whether the main lip of the oil seal contacts the shaft securely all the way around it. The second important test is whether it does so when shaft, bearing and seal are all installed in the engine. Aside from that, and making sure the seal is installed the correct way around, without any trauma to the seal's lip during assembly, it should work. Note that it is desirable to lubricate the seal lip before you push the shaft through it.

Please post some pictures as you go along with the assembly process. I still don't have any clue as to why the seals leaked on your previous tries at assembling the engine. There is still some mystery here, and it has the capacity to bite us on the backside.

Ok thanks heaps Grumpy, will keep you posted with pics.

I'm going to press seal 2mm . There are no grooves in the shaft that I could find with my fingernail. Not forgetting to grease oil seal lips first. Hope this is right.

If this fails I will move the seal even higher up the shaft. This is at least 2 mm higher than where I normaly would have pressed it in plus it was very tight fit . A lot harder to press in this seal from the others previously. There was no play in the crankshaft where as before with the old bearing there was a very tiny bit of play and I mean very little . Will let you know how it ends up.

That looks like the dirt-excluding lip on this side, which would make it the right way around. The "real" sealing lip is always a smaller diameter than the dirt lip, so it looks right so far.