# Gears or prop slipping, advice?



## catman529 (Sep 7, 2012)

here is another quirk I found with my 5 hp Briggs air cooled motor. last week I ran about 25 miles up and down the river before it started to happen, but cruising along at full throttle the engine suddenly revved a bit more and the boat slowed. Seemed very much like the prop was slipping. So before my next trip (last trip I took the boat on) I tightened the bolt down and it was in fact a tad loose. So on my last trip I was headed back to the ramp after a day fishing, and yet again my motor acted up. I could not run at full throttle without something slipping up pretty badly. Pulled the boat out and checked the prop - bolt had not loosened much if at all, but I double tightened it down as tight as I possibly could just in case. have not run it since then. Wondering what might be wrong if it's not the prop slipping? Does the nut in the prop have to be torqued down very tight or could something else be slipping up?


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## Johny25 (Sep 8, 2012)

Not familiar with B&S motors but the prop nut does not have to be cranked down very tight usually. The prop sleeves over a spline shaft that keeps the prop from slipping. The nut merely keeps it from coming off the spline. I would not advise over tightening the prop nut. Usually I seat the nut and then a quarter turn or so just to get the cotter pin through the castle nut. 

Sounds like either your engine is coming out of gear (which would make a clunking sound typically) or your prop hub may be spun


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## catman529 (Sep 8, 2012)

I don't think it's coming out of gear, it sounds like the gears might be slipping.


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## Johny25 (Sep 8, 2012)

I would check your prop hub first, as that is the least expensive to fix. If it turns out that it is ok then you have other problems, none of which are usually good : (


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## Charger25 (Sep 9, 2012)

I agree with Johny

It's been my experience that if the hub has slipped , you wont get up on plane. Meaning that the boat will try to but then fall off and the engine will rev up. It will do this every time and you should not hear any mechanical , metal on metal sounds. If you can get yer hands on a spare prop it would eliminate that variable.


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## catman529 (Sep 11, 2012)

my boat doesn't get on plane with it anyway, so I can't tell by that. I can't tell for sure, but when the engine revs and the boat slows, there might be a bit of a grinding noise but it's not that noticeable.


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## sawmill (Sep 11, 2012)

I would say that anytime you put power to your prop if the gears it would slip. If the hub in the prop was bad it may not act up until you got it under a load


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## catman529 (Sep 11, 2012)

sawmill said:


> I would say that anytime you put power to your prop if the gears it would slip. If the hub in the prop was bad it may not act up until you got it under a load


the hub is an easier fix, right? I hope so cause if you are right then that's likely the problem. When it started acting up, I could run at 1/2 and even 3/4 throttle with no problem. Just started slipping at or near full throttle.


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## Johny25 (Sep 11, 2012)

Yes take the prop to a prop shop. And also get yourself a spare incase it happens again. Best way to find out if your prop is spun is to put your spare on that you know is not spun


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## sawmill (Sep 11, 2012)

catman529 said:


> sawmill said:
> 
> 
> > I would say that anytime you put power to your prop if the gears it would slip. If the hub in the prop was bad it may not act up until you got it under a load
> ...



Yes the prop is an easier and cheaper fix. Are you sure it has a rubber bushing in it. I know a guy that has an early B & S that has a shear pin in it. Check yours to be sure


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## catman529 (Sep 12, 2012)

sawmill said:


> catman529 said:
> 
> 
> > sawmill said:
> ...


I have the illustrated parts list manual for this motor. I will go and see if I can find it and look at the prop mechanism.


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## Pappy (Sep 13, 2012)

Okay........10 posts and nothing has been determined. 
If you want to know if your prop is slipping on the hub. *Mark it!* Run it and check it. Draw a line across it, install it, and see if the line is still lined up after you feel it slip.
Second - check the gearlube. That will tell you if the gears are "slipping"............ Hint - once gears "slip" they are done. Period. 
A clutch mechanism, however, may slip and recover. I haven't looked at a diagram of the gearcase. If it is a simple Fwd/Neutral case with no reverse it probably has a clutch spring of some sort in it and that may be slipping. Again, I have not looked. If it is a clutch style and it has slipped repeatedly it will still have to be replaced.


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## catman529 (Sep 14, 2012)

all right, here is the parts list taken on my cell phone camera, hope it is clear enough.

https://i1230.photobucket.com/albums/ee485/catman529/Mobile%20Uploads/imagejpeg_2-2.jpg

Part 3032 is the Clutch/Pin kit. You can see the forward/reverse gears as well. Which parts in this diagram do I need to check? Sorry I am completely new to boat motors, this one is my first.


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## sawmill (Sep 14, 2012)

Item 3007 shows your prop and the guts of it. It looks like it has a rubber hub in it. I would guess that is the part that is bad. You said it has a gear shift, put it in gear and try turning the hub if the gears are bad it should just slip as you turn the hub. Before you do this pull the plug wires to prevent it from having an unexpected start. It you can get it to turn you should feel the compression of the engine which means your gears or ok. You can also take the plugs out of the engine and with it in gear you should be able to turn the engine over and feel air comiing out of the plug holes meaning the gears are good. The guts of the hub has to be pressed in at a prop rebuild shop. GOOD Luck


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## Pappy (Sep 14, 2012)

catman529 said:


> all right, here is the parts list taken on my cell phone camera, hope it is clear enough.
> 
> https://i1230.photobucket.com/albums/ee485/catman529/Mobile%20Uploads/imagejpeg_2-2.jpg
> 
> Part 3032 is the Clutch/Pin kit. You can see the forward/reverse gears as well. Which parts in this diagram do I need to check? Sorry I am completely new to boat motors, this one is my first.



First off you need to mark the propeller as asked. Simply remove the prop and draw a line with a marker across all parts. Run the engine until it slips then remove the prop and see if the line is still lined up. This will tell you whether or not it is the prop. 
You can do what Sawmill asked as well............whatever way you want to go just lets get off dead center here and do something!
Lets not over complicate this! Once you get the information on the line we can go from there. I looked at the photo and understand the gearcase now.


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## sawmill (Sep 15, 2012)

Pappy said:


> catman529 said:
> 
> 
> > all right, here is the parts list taken on my cell phone camera, hope it is clear enough.
> ...



You sound like you are in a hurry :lol: I would have had it fixed the first day it acted up if it was mine.But it is a good thing we have a web site to go to now to get help. In the old days it was trail and error


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## catman529 (Sep 15, 2012)

Thanks all for the advice.

I don't think the gears are bad... a few nights ago I put it in gear and turned the prop (Forgot to pull the plug, oops) but it wasn't hard to turn the engine with the prop, so it's hard to tell that way if anything is slipping. I could hear the compression release in the engine when I turned the prop. No sound coming from the gears. Only a 5 horse so I guess it's not hard to turn it by hand?

I will take the prop off, draw a line, and will hopefully be fishing tomorrow with the boat so I will get to test it. There is no nearby boat ramp so I can't just go run it in the water anytime.


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## catman529 (Sep 15, 2012)

Update -

Just took off the prop. The hub looks in perfect condition but I marked it with white paint just in case.

Think this might have been the problem?












Some of the fishing line was melted together. Cut it all off with scissors and re-installed the prop. Do you think this could have damaged the clutch, or could there still be some other damage unrelated to the fishing line?


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## Pappy (Sep 19, 2012)

Check the gearlube to make sure the line didnt ruin the seal. Draw the line and go run it.


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## catman529 (Sep 19, 2012)

I don't think the line ruined the seal, at least no oil has come out, hopefully no water has gone in either.

I ran the boat on Sunday on the river, about 15-20 miles. Maybe half of that was at full speed and the rest was slowing down or dragging the boat through shallow riffles. The motor didn't slip up once though, which was nice. I haven't checked the hub yet but I would guess the mark is still lined up.


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## Pappy (Sep 21, 2012)

Any time you have fishing line around the propshaft seal you need to check the gear lube for peace of mind if nothing else. 
Loosen the bottom drain screw and allow a little to seep around the screw and see if it is milky or not.


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## catman529 (Sep 21, 2012)

OK thanks. Will do that next time I am at the motor


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