1963 Evinrude 40hp Lark V -- float needle problems

[SteveVT]

I recently did a lot of repair work on this engine, including a carb overhaul. Boat's been out 10 times. I've had three occasions where the carb started to flood, and gas poured out of the top of the carb. The first two times it was debris from a bad NOS fuel pump gasket, which deteriorated from ethanol (replaced since). I've removed and cleaned the carb 3 times, and that is a real pain on this engine.

It has a new filter and fuel pump rebuild, as well as the carb overhaul. Debris didn't seem to be the problem this last time. Gas is clean and no obstruction in the needle jet when I checked. But for some reason the carb needle will still sometimes let fuel past when it should be closed. Both the jet and needle were replaced new with the overhaul -- OEM parts. Float adjusted level. Clip is in place.

I'm wondering if it's possible that over-pressure from the fuel pump could cause a problem like this? Or is there any other possible cause (besides dirt) that I don't know about?

 

[Joe Reeves]

Assuming that the float needle valve and seat are perfect, and the clip is attached so that when the float drops, it pulls the needle down, it's possible that you're allowing the float to drop down too far which could allow the needle to **** and jam (if possible).

.(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

 

[oldboat1]

Know you've done a lot of work on it. Were fuel lines replaced?

 

[lindy46]

Did you replace the float?

 

[oldboat1]

Either the carb float or the insides of the fuel lines may be breaking up, giving you debris. Running a solvent in an old fuel system can contribute to that. It's not really the fault of the solvent which is just doing it's job -- calls for parts replacement.

 

[SteveVT]

Thanks kindly Joe, Oldboat, Lindy,

To answer questions first:

I didn't use solvent in the lines.

The carb float, needle, orifice and clip are all new, OEM-Bombardier.

One problem I did find was the new float valve orifice washer was made out of hard plastic, and was too large. It was wider than the orifice jet body and It would catch on the back tab of the carb float sometimes (by tab, I mean the stop.). This interference would keep the float from lifting sometimes.

Another difference was that the new needle was Viton (I believe) tipped, the old one was all metal.

Also the old float and needle didn't have the wire retainer clip. I did install it on the new one however -- but I did wonder if maybe that's a problem.

I hadn't replaced the motor's internal fuel lines, and though they looked good,

I replaced them today with new.

Today I also added an in-line fuel filter just before the carb.

I believe the original type filter in the sight glass works by filtering the incoming fuel with a flow from the inside of the mesh bag out to the outside and then to the carb. That is why the NOS sight glass gasket could shed bits into the carb -- because that part of the sight glass is AFTER the filter, and leads direct to the carb. Apparently that gasket wasn't ethanol proof.

That NOS gasket has been replaced with a new good one, and the carb was cleaned twice after that. This gasket looks fine.

The new inline filter should filter everything up to the carb.

Anyway, I'm taking the boat out tomorrow, and hope the new lines and filter will solve the problem. If not I'll take the carb apart again and check the float angle. I did adjust it to be level upside down, not slightly higher, Joe, but will do that if I have problems tomorrow.


Thanks again for you guys suggestions!

 

[F_R]

Not saying you did this, but lots of people do. The wire clip does not go through the hole in the float. Instead, the clip simply hooks over the edge of the float arm.

 

[SteveVT]

Thanks F_R, no problem, all advice and suggestions gratefully accepted.

The clip was installed on the arm correctly, as you mentioned.

 

[SteveVT]

All went well this morning for about 10 minutes of low speed cruising (no wake zone), and then after we stopped to fish for a few minutes, I just couldn't get the motor started again. Arggggh!

Now that is NOT the same problem I had before, with the carb flooding out of the top into the engine compartment. It didn't seem like a stuck float needle problem. When I squeezed the fuel line bulb there was a definite hard stop -- and fuel didn't flow out. So I don't think it was a float problem.

I tried both manual choke, and choke off. I pulled the plugs to see if they were flooded. They seemed oily, but not gassy. I wiped them off. Tried again. No go.

I drained the carb. There was a full fuel bowl's worth that came out.

I squeezed the bulb and had fuel coming out of the carb drain, as it should. No blockage. The fuel looked clean.

We used the trolling motor to get back.

My feeling is, it wasn't flooded, but starved for fuel. I'm guessing the idle jets are clogged. So I'll pull the carb off tomorrow and clean it.

The only dirt I can imagine that could be in the carb would have been left over somehow by replacing the fuel lines, and adding the inline fuel filter yesterday. I suppose that could have happened.

If I clean it out again, I can't see how dirt could get in there again with new lines and two filters in place.

Getting discouraged.

 

[SteveVT]

Well I suppose it could also be an ignition failure. Kinda felt like that, because nothing I did caused it to even pop. It was just straight out dead. I'll check the wiring tomorrow and do a spark test before pulling the carb.

Pulling the carb is a pain, because I have to first remove the recoil housing, the generator, it's pulley, the starter motor, its brackets, and several linkages, plus about 6 hose connections to get to the stud nuts. This is a hot water automatic choke carb.

 

[racerone]

Does spark jump a gap of 5/16" , yes or no ?

 

[SteveVT]

Yes, racerone.

Fuel overflow problem returned this morning when I lowered the engine into the test barrel, and pumped up the squeeze bulb. So back to having to take off the carb.

If there's no apparent float/needle obstruction, I'm going start suspecting that there's something wrong with the new carb parts installed from the overhaul kit.

Like I said, the original was a metal tipped needle valve, not Viton, the original didn't have a valve clip, and the original had a smaller fiber, not plastic, jet orifice washer, that was thinner and smaller.

In a way, I'm hoping I'll find some obstruction, since that will solve it, now that there are all - new fuel hoses, and a new inline paper filter added.

It's impossible for any detritus large enough to block the needle to get into the carb at this point. If it still has the problem, the float parts are faulty.

 

[SteveVT]

I found no debris or dirt in the carburetor or float needle jet.

I removed the needle jet and needle and clip. And I compared them with the original parts. They are not the same (see photo). Original on right.





The orifice in the jet is much smaller for the original part, and its needle has a much longer taper. It's also all metal, and has no clip.

Fuel comes in from the bottom of the orifice and pushes on the needle tip. That tip must resist that pressure, when closed. Because of the smaller hole and longer taper, I think the force from fuel that the needle needs to counteract is smaller in the original design than the new replacement. For the most part, problems have happened at high throttle, or when squeezing the primer bulb, when fuel pressure is highest.

I noticed when pushing sideways with a finger that the original also has less tendency to **** off center, because the body clearance is closer

FYI the replacement was included in "BRP Evinrude Johnson Genuine Parts" Carb Repair Kit, P/N 439074. It's the part listed for this year and HP engine.

I'm thinking of reinstalling the old needle and seat.

 

[oldboat1]

Those brass jets should be bright and shiny if new or cleaned. Use the new seat with the new needle and clip, old seat with the old needle. Washer goes under the flange of the seat. Test (and measure) spark with an adjustable, open air tester ($10 or so). Clean the carb with a solvent strong enough to cut through varnish from fuel.

 

[SteveVT]

None of the above was the problem oldboat. If you read through all of what I have written so far:

1.) the problems occurred with the new seat and needle back when it was shiny new a month ago and ever since. Everything was installed properly.
2.)I know where the washer goes.
3.) I already tested the spark and already stated it was good. The problem wasn't electrical, it was flooding.
4.) This motor has been running, the only problem was this: It flooded out at times with gas coming out of the carb. Not always. Sometimes. Spoiling every day I took the boat out.

And I have the true cause tonight after tons of wasted time, wasted fishing days, wasted tear downs and some wasted money on an OEM carb rebuild kit.

Needles are fine, both of them.
Seats are fine, both of them.

THE ACTUAL PROBLEM IS:

BRP increased the diameter of the cork float and its thickness slightly, compared to the old, and it rubs against the fuel bowl housing. There's no way to reduce this diameter without removing the new cork's anti-fuel coating.

I found this out by listening to the float fall when I inverted the carb with the float bowl on, and with it off. No sound sometimes when I had the bowl on.

If I hold the floats up together, I can see the new one is a little bigger.

If I replace it with the old float, I can hear the float drop every time I invert it.

So much for OEM parts ........

what a waste.....

 

[oldboat1]

Yes, had read it all some time ago. Used seafoam in old fuel lines, for example -- potentially an issue, if the carb wasn't disassembled and cleaned after that contamination (exacerbates the problem). Think it might be technique rather than parts -- hope you solve the actual problem.

 

[SteveVT]

Old Float vs New Float:

The size and clearance difference doesn't look like much in these photos, but it's enough to spoil your day.

 

[SteveVT]

oldboat -- I don't understand....

 

[oldboat1]

Soak the carb, measure float drop, measure spark as indicated above. Don't use an inline tester, remove plugs, and insure it's cranking fast. Get a good ground for the tester.

 

[SteveVT]

Are you reading any of this thread?