60's Evinrude Sportwin carb problems

[cr9c1]

I've got a mid to late 60s Evinrude Sportwin 9.5 hp outboard motor with carb troubles. I've tried two different carbs. One has a high speed issue, where it wont open up all the way, about half max, and the other has a low speed problem.

The one with the low speed problem seems to me the most likely candidate to fix. Ive tried two different low speed mixture screws and no matter what I do it just does the tunking thing and stalls out below about 1500 rpms or 2000 or so. I took the guts apart and blew all the jets out and cleaned it up real nice, and cleaner flows through all the ports effortlessly. The needle, float, and seat all look really good and appear to be brand new.

Air flow is not a problem because the cowling is off while testing. It does the same thing in a barrel as it does on the lake. You can fool it and get it into gear by using the choke but it still surges till you get up to full throttle where it runs fine and has plenty of power.

Anyone have any idea what I could do to fix this, or have a carburettor they wish to sell? If so reply/pm/email. Email = ffcpross at verizon dot net.

Everything is as it should be on the linkage between the ignition plate and the throttle as well. Its identically to a motor I had about 4 years ago, opens up and moves the same way and everything. I have also swapped in a set of good known coils, points, and condensers to rule those out as well as new spark plugs.

 

[cr9c1]

Re: 60's Evinrude Sportwin carb problems

I read some stuff about core plugs. I never knew they existed really, or I did and never knew you could remove them. Perhaps there is some gunk behind them?

I assume they can be gotten at a dealership/evinrude/johnson shop. How do you remove them, and how do you install the new ones? Im fairly certain I can get this carb working if I can figure out what the heck is wrong with it.

 

[lexkyboater]

Re: 60's Evinrude Sportwin carb problems

This sounds familiar. I just successfully diagnosed and fixed multiple problems on my 71 Johnson 9.5 not revving out thread. If you haven't read, you might want to check it. My main problem was set up that caused it not to rev out. You say you've replaced low speed needle, but did you adjust it according to Joe Reeve's carb set up suggestions? Best to get it idling at max rpm, turn that idle mixture knob in till it coughs, back it out 1/4 turn and you've got it.

Definitely remove and at least blow out (preferably soak in carb cleaner) and rebuild the carbs if you haven't already. It's $25 well spent. If it's not idling with the one carb you want to fix, that indicates a fuel flow problem through low speed circuit if you've verified ignition and compression. Definitely drill or use an awl to get those core plugs out. Rebuild kit comes with new ones. See pics of my carb with the core plugs out. #1 shows gunk behind top core plug and blocked lower ports (even though I had originally tried to blow these out the first time I cleaned with the core plugs in - obviously I didn't get it out). That gunk is just ripe to block ports in the future. #2 shows light magnifying problem, #3 is clean. #4 shows the idle speed port - on the right is where the idle speed screw goes and the arrow to the left is where gas is flowing. The brass tube is the high speed pickup. #5 is the float chamber base with the high speed jet on the right and the drain plug, and the arrows point to idle speed speed port and high speed port. The high speed jet feeds both the idle speed and high speed ports, as that's the only port out of the float bowl. To put the new core plugs in, just insert then use a dowel or something similar to flatten the new plugs out to snug into place.

 

[cr9c1]

Re: 60's Evinrude Sportwin carb problems

I pulled out the core plugs but to my suprise, the large one had a plastic bushing or something behind it. To be safe, I took a bad carb and tried to remove it. No luck. The smaller core looked fine, no dirt in it or anything. All ports flowing freely, however, still no idle.

As far as the plate the carb bolts to that is bolted to block with the 4 bolts and one flat head screw, is there anything in it that may plug up and cause the issues im experiencing?

I'm at a loss here. Carb looks good as new, no dirt or anything it. Clean as a whistle. Still sneezing and stalling out below 3-2000 rpms. If I close the choke half-3/4 way it will stay running.

 

[tashasdaddy]

Re: 60's Evinrude Sportwin carb problems

what do the reed valves look like behind the carb, if they are varnished in the slightest they will cause all kinds of problems. closing the choke indicates a fuel delivery problem, it's starving for gas. is the vent open on the tank, are you sure the fuel pump is good.

 

[cr9c1]

Re: 60's Evinrude Sportwin carb problems

Positive the fuel pump is good. I'll try running without the gas cap on but it runs fine at WOT, just coughs and dies at an idle.

 

[tashasdaddy]

Re: 60's Evinrude Sportwin carb problems

whats your compression numbers, then try this http://forums.iboats.com/showthread.php?t=167352

 

[cr9c1]

Re: 60's Evinrude Sportwin carb problems

Can't give compression numbers yet, but I know it feels like it has quite a bit. I've had the same model with lower compression that ran great.

I've tried the thing described in the thread as well. No go.

Can't get it to idle below 2-3000

 

[lexkyboater]

Re: 60's Evinrude Sportwin carb problems

You said you have a spare carb, does that include a spare float chamber base? And have you tried swapping them? The problem may be in the float chamber base and not the carb. You said you blew out and squirted fluid through the carb, but did you also blow out/clean the port I pointed out in the base (where the high speed jet goes)? Did you remove and clean the high speed jet, and did you verify the orifice is .048 inches in diameter? If the float chamber base is damaged, that's going to be a lot cheaper than a new carb.

If you have one carb/base combo that doesn't idle and the other doesn't run at WOT, you might be able to isolate the problem. If you switch them, it would be interesting to see if the problem follows the base. Sounds like everything else on the engine is good since one carb will run and the other will idle. Assuming that happens everytime, seems that it can't be a reeds problem or anything else on the engine, sounds like it's isolated to carb/float base.

The carb/base combo that doesn't idle may also be warped and it's sucking air or the float base to carb gasket is broken and it's sucking air and is too lean to idle. Can you verify with a flat surface like glass that the base and/or carb is not warped? If you tighten the screws too tight this can happen, better to be too loose than too tight. What happens when you try to set the idle mixture? When you seated it, did you screw out 1 1/2 turns, and have you tried more or less? Did you try increasing the idle speed near the handle where the gas line comes into the engine to keep it idling? Can you take some pics for us?

On that bushing behind the core plug, maybe someone used that to keep it from leaking? I would think that as long as it doesn't block ports, it should be okay. Those core plugs are only access ports, seems it would be better if they would have used screw in plugs instead. Keep in touch and keep posting to let us know how it goes.

 

[cr9c1]

Re: 60's Evinrude Sportwin carb problems

Well. I haven't tried a different float base. I've been using the same one and just swapping the top half of the carb over. The other one will idle but not idle good. I destroyed it by trying to remove the plastic bushing in behind the larger core plug. Couldn't get it out. I'm fairly certain its isolated to the carb since I've been using the same float base. The one that doesn't idle will get the boat up to speed but it surges throughout the RPM range until it reaches WOT.

I've tried manually adjusting the throttle on just the carb to get it to idle, but it doesn't do anything. It just bogs down. I dont think its getting enough air into the cylinders. I could be wrong though. I do have another float base I can try, and I will to rule that out as a problem but all I know is, I have disassembled every part I know how on the carb and can't get it straightened out. How do you remove the high speed jet? And you are referring to the piece of brownish/gold metal tube sticking out of the bottom of the carb, right?

 

[cr9c1]

Re: 60's Evinrude Sportwin carb problems

Ok. Fixed the low speed and high speed problems. Purrs like a kitten now.


Only problem left to figure out is when the motor cover is on it acts like its starved for air. When its off, it runs great. It doesn't run totally horrible with the cover on but there is a big difference between taking it off and leaving it on. Any ideas?

 

[lexkyboater]

Re: 60's Evinrude Sportwin carb problems

Hey that's great news! But, don't leave us hanging - what was the fix???

On the problem with the cowl, some other people have told me the seals around the drive shaft and water tube, if not in good shape, can be a problem if it won't run with the cover on. Too much exhaust can make it's way back up the lower unit cover and up into the engine area, and starve the engine of oxygen. The fix is to replace those seals, which usually come with the water pump rebuild kit. If it's been 2 or 3 years since the pump has been replaced, you should go ahead and rebuild it. Maybe even the housing, as it has a tendency to be warped, which reduces the efficiency of your pump. See attached pic #1 for the seals.

On removing the lower unit, there's 4 bolts that hold it on. See pic #2. You'll want to put it in forward, remove the bolts, then *remove* (not loosen) the shift rod coupler screw, pic #3, to gain access to the water pump and seals. You'll want to grease the drive shaft end, and the water tube seal before reassembling. You might want to take a flat blade screwdriver and open up the shift rod coupling a little too before reassembling so you can get the lower shift rod in the coupling easily. Make sure that you get the end of the lower shift rod in there so that the screw goes in the notch properly so it locks it in right. I'd recommend at least going to library and checking out a manual or buying one if you plan to keep the engine. --Steve

 

[cr9c1]

Re: 60's Evinrude Sportwin carb problems

The 3 small holes in the bottom of the throat of the carb were plugged solid. I was able to use fine tip cleaners to get two of them but the 3rd required some wreath wire, compressed air, and WD-40 (To verify flow)

I guess I'm having a hard time wrapping my brain around the driveshaft seal and water pump seal allowing exhaust back up into the engine area. The only thing I can see that would do that is the gasket where the power head meets the midsection, or the manifold gasket or whatever you want to call it.

I should really have a repair manual for these but I've build one out of two so I am quite familiar with how they work. (Not this particular motor that I built but one years ago when I was around 16-17 years old.)

I'm fairly certain its exhaust causing it I just need to track the leak down. If those seals are the buggers then by all means I will replace, but like I said. Im more inclined to think its coming from somewhere else.

 

[lexkyboater]

Re: 60's Evinrude Sportwin carb problems

Those three holes don't seem to have any ports feeding gas or air to them, but they're obviously important. Good to know the symptoms of those being clogged - sounds like lack of idle and surging. Good to know to help diagnose other people's carb issues.

On that exhaust leak, you can get the parts breakdown for your motor at http://epc.brp.com/default.aspx?brands=ej&lang=e. Pick Johnson then choose the year and HP, then the powerhead and starter breakdown. That motor has an exhaust cover with 3 gaskets that could leak, but the more common problem and the easier fix is to just replace the water tube and drive shaft seals. You really should replace at least the water pump imeller too at least every 3 years or if it's been sitting. The seals and water pump are in a harsh environment and break down pretty quick. Keep in mind that the whole lower unit around the drive shaft water pump housing is to let exhaust pass through to that exhaust port on the back of the lower unit. It's just open and those seals (and exhaust cover gaskets) are what keep the exhaust out of the engine area. Keep in mind also these motors don't really run well in a barrel without picking up exhaust and have a tendency to not idle well then.

On the lake, does it have a problem with this at WOT? Mine, even after seal replacement, gets a lot of exhaust that rises to the engine area in a barrel and does better w/o the cowl. But on the lake is fine. This is a known issue - see the others commenting on this in my 1971 Johnson 9.5 HP Not Revving Out thread. Also, mine runs a letter better w/o the cowl at WOT and iwombat says this is due to it leaning out because it's getting more air. Typical I would think.

 

[cr9c1]

Re: 60's Evinrude Sportwin carb problems

It'll run on the lake at WOT fine but it bogs down some. Minute I lift the cover off it takes off. It still stumbles and eventually will stall out with the cover on at the lake though. All the gaskets on the engine itself are fine, but exhaust is coming up from down below somewhere. Its just a matter now of finding out where. I really don't want to have to split the two halves apart if I dont have to but I'm running out of options on finding out where this leak is coming from. I never had this problem with my other 9.5 Johnson, and this is identical other than the Evinrude Sportwin branding.

 

[iwombat]

Re: 60's Evinrude Sportwin carb problems

It's the shift shaft seal that's the bugaboo on this model. It's a little accordian style rubber boot that's prone to crack and split. It lets exhaust air into the top chamber and causes the symptoms you describe. Problem is, the boot is no longer available.

 

[cr9c1]

Re: 60's Evinrude Sportwin carb problems

I found a boot on some parts motors that appears to be in good shape. How hard would it be to remove it? I don't want to tear it up in the process.

 

[cr9c1]

Re: 60's Evinrude Sportwin carb problems

Okay. Disassembled completely. I found the small boot on the shift rod that sits middle of the midsection was not even close to how it should be. It wasn't attached to anything. So, I took the 3 screws out of the metal plate below it that the cooling tube and shift rod goes through, put some gasket goop on it and reattached it as close and as best I could.

I also put some gasket goop on the powerhead-to-midsection mounting piece.

After I reassembled, I of course started it up in a test can and it not only seemed to run better, it was pumping a lot better too. I still notice a distinct difference between running with the engine cover on and off, but it doesn't spit, sputter, and stall with it on so I think I may have got it.

I want to take this oppurtunity to thank iwombat and lexkyboater for your continued assistance in helping me diagnose and correct this problem. I'll post another update as soon as I get it out on the lake and try it.

 

[iwombat]

Re: 60's Evinrude Sportwin carb problems

With this motor you'll see a difference with the cover on vs off. With it off it leans out quite a bit and seems like it runs better. However, it's not getting quite enough mix to maintain healthy over the long term. The key is, does it idle and run properly with the cover on now?

 

[lexkyboater]

Re: 60's Evinrude Sportwin carb problems

For my education, can one of you elaborate on what was gasket gooped? Is it #83, the shift rod seal? To get to this, does #1, the lower cover assy need to be removed? You don't have to pull the powerhead, right? When you remove #1, I'm assuming there's bolts (#8, housing to powerhead screw) you take off to get to those seals? See pic from BRP's parts catalog.

It sounds like #39, the housing to cylinder gasket, was also gooped? I think I misunderstood a previous post in another thread about #87, the exhaust housing seal. What condition was #87 in? It seems that the water tube and drive shaft seals in the lower unit don't have much of an impact on exhaust circulating back up into the engine. Sorry about that! --Steve