55 hp flooding question

J

jmk

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Will bad reeds cause fuel to build up in the lower end. I have rebuilt the carb. Gas shuts off but while running it has fuel coming out of a small hole by the prop. When I stop it bubbles up in big white foamy globs spreading out at the surface with the smell of gas making a big slick. I mean a slick about 30'. The motor seems to run fine.
 
J

Jiggz

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Re: 55 hp flooding question

Bad reeds can do that since fuel mixture will be doing a blowback in the carb but if this happens then the engine should not be running fine but instead should be misfiring. You need to remove the cowling while the engine is running and watch the carbs if there is any fuel overflow coming out of the carbs vent holes (tiny hole on the side) indicating a bad float or needle valve. If there is none, then it could also be a bad seal on the crankshaft leaking unburned fuel through the legs and LU.
 
J

jmk

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Re: 55 hp flooding question

There is no fuel leaking from the carb. The cowling is dry. This motor has over heated a couple times when the impeller quits. Are you talking about the top seal on the drive shaft?
 
jerryjerry05

jerryjerry05

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Re: 55 hp flooding question

55hp,year? Model#?Serial#
Check the fuel pump diaphram.
Using excess fuel?
Check the oil in the lower unit, any water?
Possible it's leaking bad.
The fuel recirculation system clogged,if it has one?
 
J

jmk

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Re: 55 hp flooding question

Its a 1971 557hc serial 3327 It has a newly rebuilt carb, fuel pump with new diaphragm as of a couple years ago. it's always had this fuel problem. I even tried a different carb. The lower end is good. It's gas that is coming up not oil. It's coming out of a hole in the motor leg above the gear box at the bottom end. Its supposed to come out there but not like it is. I never did check compression on this motor because it starts and runs so well. Do you think maybe blow by would cause it to have excess unburned fuel spilling out of the bottom? The other thing I was wondering if maybe timing could be off a bit. I don't know how to check that. Maybe I will just get rid of this motor. I hate the fact that it runs so smooth and has a good idle that I am going to can it. I just cant be leaving all that fuel with the lake and ramps.
 
tater76

tater76

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Re: 55 hp flooding question

White foamy globs is lower unit oil/water mix. Do as Jerry said, drain the oil in the lower unit. I would bet money it is milky. Replace the impeller while your there. Its a yearly maintenance part, and cheap insurance against overheating/ruining your motor.
 
J

jmk

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Re: 55 hp flooding question

its not the gear oil. I have changed it and its fine I put a new impeller in every year. Besides gear oil doesn't smell like a gas spill. Thanks for you thought though.
 
J

jmk

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Re: 55 hp flooding question

I bet when the motor over heated that bottom seal on the motor on top of the driveshaft melted enough to leak. If the fuel and oil in the crankcase was dropping down the driveshaft it would have lots of oil and smell like gas right? Then again when I asked this question and researched it on here last year a guy told me that the hole was for unburned fuel to leak out so it must come out of the cranckcase and drip down into the leg some how. I have read other people complaining about this in other posts too. Their conclusion was that hole was for unburned fuel. Seeing I have so much unburned fuel dripping down I must not be burning much fuel and it builds up faster and drips down more. Now saying this does this spark any more thoughts to what cause excess un burned fuel? Timing? Blow by? Can the motor still run fine with both of those? I will do a compression check. I will have to read up on the timing. This site is a great resorce, and a tool. I appreciate all the help I can get from here, Thanks, John
 
jerryjerry05

jerryjerry05

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Re: 55 hp flooding question

Not sure what recirc system you have.
Post some close up pics of the stbd side and front of the motor.
Find a parts diagram if its close to the one on boats . net The pic is a 75/45 .it should have these parts.
#44/45/46/47 is part of the recirc system Clean this and see if the problem stops.
If the lower seal was bad I don't think it would run that good??
 
tater76

tater76

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Re: 55 hp flooding question

My 55's do drip a little unburned mix too, but its not excessive. Have you checked spark? They will run on just one cylinder, pretty well in fact. This would explain excess unburned fuel. What kind of performance are you getting out of it? I say that because when my 55 was running on one cylinder, it was still able to push my 16ft boat at 15mph.
 
J

jmk

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Re: 55 hp flooding question

It does about 18 mph. Its pushing a 19' aluminum boat about 1400 lbs plus me and a passenger. It has run on one cylinder when the coil went bad. It was pretty slow with one, but ya I know what you mean. They do run on one. I will check the plugs and see what they look like. I have put new ones in. I wonder if I do a decarb on it if it will help.
 
J

jmk

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Re: 55 hp flooding question

stbd side.JPGstbd side front.JPGfront lines.JPGhole.JPG

I cant find the diagram your looking at. When I go to ********** and look up my motor they just have the carb and fuel pump no recirculation diagrams. What do you mean by 75/45? Hp?
 
tater76

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Re: 55 hp flooding question

he means a 1975 45hp. The 55hp recirc system has a screen that gets plugged up with junk sometimes. It sits behind the plate that the interlock switch bolts to in pic #1. You will likely need a new gasket when you reinstall it. Clean it out, and see what happens. I think your motor is performing as it should. 18mph on that big of a boat is about as good as your gonna get with a 55hp.
 
J

jmk

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Re: 55 hp flooding question

tater are you saying take the plate off above the fuel pump that has the wire harness clamp? It has a hose from the fuel pump going into it.
 
J

jmk

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Re: 55 hp flooding question

okay looking at the 75/45 you do mean the plate right behind the switch. It didn't look like a plate to me in the picture, but when I go to the diagram that jerry is talking about the parts 44 -47 are right behind that electric switch. is this right? I don't want to take the wrong plate off. I copied the diagram hopefully it will be legiblediagram small.JPG.
 
J

jmk

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Re: 55 hp flooding question

part 47 is CYLINDER DRAIN REED STOP
$0.46 $0.46 2 OBSOLETE
part 48 F18160-1
REED, CYLINDER DRAIN

clean these and the screen? The screen isn't on the list.
 
tater76

tater76

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Re: 55 hp flooding question

Yes that is the right plate. It is long and sits vertical on the block. The screen will be inside it if I remember correctly, and you can clean it with carb cleaner or soap and hot water. I may have an extra gasket if you cant find one. I can't read the numbers on the diagram, too small for my bad eyes lol :)
 
J

jmk

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Re: 55 hp flooding question

Okay thanks, I will clean that out. My friend has gasket material I can make a new gasket.
 
jerryjerry05

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Re: 55 hp flooding question

If you take it apart try to save the screen?
You can't get them from most parts places.
Take a pic of the parts after it's removed.Post it.
If it's clogged it can be the problem.
If not?? Then the lower seal is probably the culprit.

18mph with a 19ft alum boat?? The motor was probably put on without checking for the correct pitch??
After it's fixed, get someway to figure out the RPMs at WOT and then we can figure out the prop?
Propellers can wear down. My friend had a 68 60hp Johnson.He had the same prop for almost 25 years.
Never hit a sandbar and never any nicks. He was worried about it being slower than when it was new.
He got the ruler out and started measuring. Over the years it has wore down about 1/4 in. Installed a new prop and it was like new.
Still a horrible gas hog but real fast:)
 
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