Time to rebuild the carb. on a 1957 7.5 hp

BSDenning

BSDenning

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Hello Everyone. I've decided that it is time to rebuild the carburetor on my 1957 Evinrude Fleetwin 7.5 hp outboard motor. I've owned this motor for about a year and a half. I've replaced everything under the flywheel and I replaced the head gasket. Now it is running kind of rough and seems to give those little mild backfires/missfires that can normally be eliminated by adjusting the high and low speed knobs.

So, I've bought a bucket of carb cleaner so that I can soak everything overnight in the carb cleaner. I bought a brush that I can use to clean everything. I plan to go to NAPA tomorrow to buy a carb rebuild kit and I'm going to go ahead and buy a new impeller also because I've never replaced that either.

I've got a service manual and I'm going to be reading up on it.

Does anyone know anything else I need to get or any pointers to rebuilding the carb or replacing the impeller?

This will be my first attempt at rebuilding a carburetor and replacing an impeller.
 
JB

JB

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Re: Time to rebuild the carb. on a 1957 7.5 hp

Sounds like you have what you need, BSD.

One thing often overlooked in carb cleaning is the tiny passages into the carb throat. After soaking they usually blow out easily with compressed air, but to do it in a bulletproof way, remove the welch plugs in the top of the throat that allow access and run a wire through them. There should be replacement welch plugs in the overhaul kit.

Good luck. :)
 
BSDenning

BSDenning

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Re: Time to rebuild the carb. on a 1957 7.5 hp

I went to NAPA and the guy didn't have any trouble finding the water pump kit for my motor. He said it was sierra part number 18-3202. He wasn't sure about the carb rebuild kit though. He said he thought it was part number 18-7043. He told me to go look at my carburator and I should see one of the following number stamped on it: 382047,49; 383052,67; 398532; or 439071. I could not find any of those numbers on my carburator. I found a number stamped upside down on the front of the carburator near the choke switch that says 303475.

Can anyone tell me the correct sierra part number for the carb rebuilt kit I should get for the motor?

Motor Information:
1957 7.5 hp Evinrude Fleetwin
Model number: 7522
Serial number: 07630
 
T

tx1961whaler

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Re: Time to rebuild the carb. on a 1957 7.5 hp

Before you order a carb kit, make sure you don't have a cork float in your carb. If you have a cork float, it should be replaced. The float is not part of the regular carb kit
 
BSDenning

BSDenning

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Re: Time to rebuild the carb. on a 1957 7.5 hp

Thanks for the info. I went ahead and ordered the carb rebuild kit and the impeller with the wear plate. I should be able to get them tomorrow morning. The guy at NAPA said the float is not available for my motor. So, if I still have a cork float, I'll have to find somewhere to get a new float.

I have 2 questions:

First: Is my motor supposed to have a fuel fitler? My 1962 10 hp has a cylinder shaped fuel filter inside the glass sediment bowl. This motor does not have a filter in the glass sediment bowl, so I was wondering if I need to try to find one. I have a parts catalog for a 1956 7.5 hp and it shows a fuel filter.

Second: I know to replace the impeller, I'm going to have to remove the entire powerhead. Do I need to buy any additional gaskets to do this, such as the gasket that seals the powerhead to the leg or the gasket that seals the two halves of the leg together? I do have some thin gasket material that I bought at advanced autoparts a while back.
 
BSDenning

BSDenning

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Re: Time to rebuild the carb. on a 1957 7.5 hp

I got the carb. kit and the impeller with the wear plate today from NAPA. I'll be working on it ASAP! :D
 
wbeaton

wbeaton

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Re: Time to rebuild the carb. on a 1957 7.5 hp

The fuel filter is located in the glass bowl on the bottom of the carb. You should also change the cork gasket and o-ring that sit on top of the driveshaft when you do the impeller. They make up the lower crankcase seal.
 
BSDenning

BSDenning

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Re: Time to rebuild the carb. on a 1957 7.5 hp

OK, my carburator is completely disassembled and soaking in carb cleaner right now. I found the fuel filter. It was inside the glass bowl. I think I may order a new one, just because I don't know how old that one is.

I think I'm going to have to replace the float. I'm not sure if it is cork or not. It is black, but it seems a bit cracked and flakes seem to be coming off of it. I will post pictures of it.

My carb kit did not come with the gasket for the glass sediment bowl. I'm guessing I should either reuse it or see if I can order a replacement.

I will also need to order a cork gasket and o-ring that sit on top of the driveshaft for when I replace the impeller.

Here are the pictures of my float:

100_1768.jpg


100_1769.jpg


100_1771.jpg


100_1772.jpg


100_1773.jpg
 
BSDenning

BSDenning

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Re: Time to rebuild the carb. on a 1957 7.5 hp

My slow speed needle does have some slight scoring around the tip, but it doesn't look too bad. I wonder if you can tell by these pictures if I should replace it or not.

100_1758.jpg


100_1759.jpg
 
BSDenning

BSDenning

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Re: Time to rebuild the carb. on a 1957 7.5 hp

JB said:
Sounds like you have what you need, BSD.

One thing often overlooked in carb cleaning is the tiny passages into the carb throat. After soaking they usually blow out easily with compressed air, but to do it in a bulletproof way, remove the welch plugs in the top of the throat that allow access and run a wire through them. There should be replacement welch plugs in the overhaul kit.

Good luck. :)
Click to expand...

What do these welch plugs look like?
 
jbjennings

jbjennings

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Re: Time to rebuild the carb. on a 1957 7.5 hp

It's a corker BSD! I'd replace it. Could be those laquer flakes are what were breaking loose and stopping up the carb. The needle is so easy to get in/out, I believe I'd just rebuild the carb., readjust it, run it, and see how it goes before I'd worry about a new idle needle, although it does look a little grooved and could be causing your problem also.
Just my opinion,
JBJ
 
BSDenning

BSDenning

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Re: Time to rebuild the carb. on a 1957 7.5 hp

jbjennings said:
It's a corker BSD! I'd replace it. Could be those laquer flakes are what were breaking loose and stopping up the carb. The needle is so easy to get in/out, I believe I'd just rebuild the carb., readjust it, run it, and see how it goes before I'd worry about a new idle needle, although it does look a little grooved and could be causing your problem also.
Just my opinion,
JBJ
Click to expand...

Thanks JBJ, I'll replace the corker! You've got a good point about the low speed needle. I'll just continue rebuilding the carb and if I have any additional trouble, I'll asses whether to replace that needle.
 
jbjennings

jbjennings

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Re: Time to rebuild the carb. on a 1957 7.5 hp

I believe there's only one welch plug on your carb, BSD. It will be the little silver plug on the top of the carb. some folks use a pick and BARELY tap it through the plug and then pry it out. If you poke through too hard and punch through the carb body, your carb is ruined. The welch plug is a little concave piece of metal that you drop in the cylindrical orifice and tap on it in order to flatten it out and seal it in there. Some folks like to use a dab of epoxy to be sure it doesn't leak, although I've never tried it or had a problem with no epoxy. When you take out the Welch plug, you'll be able to see the 4 of 5 tiny holes that the idle fuel go into the carb throat through so you can clean 'em out really good.
Good luck,
JBJ
 
BSDenning

BSDenning

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Re: Time to rebuild the carb. on a 1957 7.5 hp

jbjennings said:
I believe there's only one welch plug on your carb, BSD. It will be the little silver plug on the top of the carb. some folks use a pick and BARELY tap it through the plug and then pry it out. If you poke through too hard and punch through the carb body, your carb is ruined. The welch plug is a little concave piece of metal that you drop in the cylindrical orifice and tap on it in order to flatten it out and seal it in there. Some folks like to use a dab of epoxy to be sure it doesn't leak, although I've never tried it or had a problem with no epoxy. When you take out the Welch plug, you'll be able to see the 4 of 5 tiny holes that the idle fuel go into the carb throat through so you can clean 'em out really good.
Good luck,
JBJ
Click to expand...

Ok, I see what you're talking about. I can see the little holes on the inside of the throat of the carburator. My kit came with 2 welch plugs. The one I need is the smaller one I believe. Anyway, so to get it out, I should take something sharp and try to tap it all the way through the plug, but not through the carb body, then try to pry it out? Sounds like a delicate procedure.
 
jbjennings

jbjennings

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Re: Time to rebuild the carb. on a 1957 7.5 hp

The first time I did one I just tapped on it until it was concave again and it will just fall out. Once you see how deep you can go after you get it out, then it's better on your nerves to use the punch/pry method.:)
JBJ
 
BSDenning

BSDenning

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Re: Time to rebuild the carb. on a 1957 7.5 hp

Ok, I got the welch plug out. I used a small drill bit to drill through it and then I was able to pry it out. I've got my new float and fuel filter ordered from http://www.laingsoutboards.com/ so I'm waiting for that to arrive.

My carburator soaked overnight in carb cleaner. Now, I'm trying to get those high and slow speed packing washers out. They're stuck in there, so I've been picking at them and they're being a pain because instead of just coming out, they are falling apart. I guess I probably should have tried to get them out before I soaked it in carb cleaner. So, other than that, everything is going pretty good.
 
BSDenning

BSDenning

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Re: Time to rebuild the carb. on a 1957 7.5 hp

Ok, I got all the old packing washers out. Now, I'm letting the carb soak in cleaner again tonight so it will eat up any left over packing that is still stuck to it.

So, I'm ready to replace the impeller. In order to disconnect the shift linkage, I have to remove the screws that hold the powerhead to the lower unit and remove the powerhead. Well, those screws are stuck! I sprayed some liquid wrench on them and tried a small battery powered craftsman impact screwdriver, but the screws didn't budge. I guess I'm going to have to figure out some way to leverage it with a ratchet or a wrench or something, but I sure don't want to break any of those screws. Does anyone have any suggestions or tips on how to get these screws out?
 
BSDenning

BSDenning

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Re: Time to rebuild the carb. on a 1957 7.5 hp

Well, I've got 5 out of the 7 screws out. The last two will not budge. They are flat head screws, which makes it difficult because my screwdriver keeps sliping off them. I've been spraying them with Liquid Wrench. Any ideas on how to get them out? I'm on the verge of taking a drill to them, but I know that is a last resort.
 
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