5.7 omc carb leak

[Nick_1987 5.7 OMC]

Yep quite impressive water fall. I'd give the threads a light coat of Evinrude gasket sealer or Permatex Aviation, both help prevent corrosion and also may keep them from getting loose.

Well today we got it done, carb was put back together, and installed. Bogging didn’t go away. Tightened the harness and that seemed to solve some of the issue. But most importantly new plugs for the job done. Boat runs like a dream. We were able to tighten those 4 bolt on the y pipe. Yes all 4 without having to pull boat out of water and pull drive and motor out. Used a 1/4 extension as well as a elbow w 3/8 bit and we got the job done. Might need a chiro or too but it’s done. Bilge is bone dry now and the leak as completely stopped. I will stop by the boat tmr and inspect. Thanks for all the help guys! One more thing. What should I have onboard for long trips? 60-80kilometer long trips, apart from fuel

 

[Lou C]

Great great great!
Spares:
Fuel filter
Belts
Points & condenser if you still have the old style ignition
Cap & rotor
Impeller wear plate & gasket
Gasket sealer
Tools to change all of the above
I also have a spare bilge pump

 

[kenny nunez]

The bogging may be caused by the secondary air valve opening too quickly.
Always have a spare alternator belt, fuel filter, points and condenser. Power steering fluid, motor oil extra 50 amp fuses. A good 12 volt test light. You probably have a marine band radio. I cannot think of any thing else but I am sure someone will have some other suggestions. Good Luck

 

[Nick_1987 5.7 OMC]

The bogging may be caused by the secondary air valve opening too quickly.
Always have a spare alternator belt, fuel filter, points and condenser. Power steering fluid, motor oil extra 50 amp fuses. A good 12 volt test light. You probably have a marine band radio. I cannot think of any thing else but I am sure someone will have some other suggestions. Good Luck

What secondary air valve?

 

[Lou C]

On the 4bbl Quadrajet the secondaries are mechanically operated but the air flaps above them (secondary air valves) are vacuum operated. There is a spring that keeps them shut till the vacuum drops to a certain level but the tightness of the spring is adjustable. If they open too soon you can get a bog because you're getting a lot more air but not enough RPM to flow enough extra fuel. You can see the flaps in this pic of the QJet air horn

 

[Nick_1987 5.7 OMC]

On the 4bbl Quadrajet the secondaries are mechanically operated but the air flaps above them (secondary air valves) are vacuum operated. There is a spring that keeps them shut till the vacuum drops to a certain level but the tightness of the spring is adjustable. If they open too soon you can get a bog because you're getting a lot more air but not enough RPM to flow enough extra fuel. You can see the flaps in this pic of the QJet air horn

The spring on mine is bolted to the block and let’s go as the block heats up.

 

[Nick_1987 5.7 OMC]

The spring on mine is bolted to the block and let’s go as the block heats up.

Unless I’ve mistaken. How can I tighten the spring?

 

[kenny nunez]

Google “ adjusting secondary air valve Quadrajet carburetor. There are videos that should help.

 

[Lou C]

look in the pic above, air valve torsion spring. Keep in mind that pic shows it with it upside down from how its installed. So when installed it is on the starboard rear side of carb air horn. Need a small mirror to see it.

 

[Lou C]

The spring on mine is bolted to the block and let’s go as the block heats up.

that's the thermostatic choke spring for the divorced choke.
the spring you are looking for is inside the air horn (top cover of carb)

 

[Lou C]

And that's not the only cause of a bog, it could be a bad accel pump piston & seal. I replaced mine last spring and it made a big difference. The old one was just worn out and/or deteriorated from the e10 gas we are stuck with using. I used a good one from Cliff's.

 

[Nick_1987 5.7 OMC]

Ok

And that's not the only cause of a bog, it could be a bad accel pump piston & seal. I replaced mine last spring and it made a big difference. The old one was just worn out and/or deteriorated from the e10 gas we are stuck with using. I used a good one from Cliff's.

Ok boys back again…. Everything is good just had something happened while cruising. We were going full to throttle like normal and then my motor reved up and I didn’t have drive. I just had this outdrive installed. Brand new by certified omc technicians. It’s almost like the tranny is slipping. If I go to min gas the boat is able to move but very slow. Once I pass 1500 it skips and engine Revs but no movement. No weird noises coming from drive, no clanking or nothing. I am able to putt back to port but I just can’t go fast. What can be causing this?

 

[kenny nunez]

It may just be a bad hub in the propeller.

 

[Scott Danforth]

Prop hub or coupler

 

[Nick_1987 5.7 OMC]

It may just be a bad hub in the propeller.

I stopped boat turned motor off and I was able to spin prop while it was in forward. I had to use some force but I shouldn’t be able to move it anyways. Could that Lena something

 

[Scott Danforth]

if its the prop hub. take a sharpie, mark the hub and the prop with a line, go for a ride. if the line moves, get your prop fixed

 

[Nick_1987 5.7 OMC]

if its the prop hub. take a sharpie, mark the hub and the prop with a line, go for a ride. if the line moves, get your prop fixed

Maybe I should go to boat with a new prop and put it on. And test it. You think that it’s a spun hub over a stretched cable?

 

[Nick_1987 5.7 OMC]

if its the prop hub. take a sharpie, mark the hub and the prop with a line, go for a ride. if the line moves, get your prop fixed

Prop fixed out prop changed ? It’s a pressed huh

 

[Lou C]

Well a stretched cable would cause the drive to jump out of gear with a CLUNK, not slippage. If when you lose drive the engine temp started to go up; that’s a sign it’s the coupler because the impeller in the drive turns at the speed of the input shaft. If it’s not spinning at engine crankshaft speed the engine temp will rise. If that didn’t happen more likely to be the prop. If you have a good prop try that & see.
Let’s hope it’s the prop a bad coupler requires an engine pull.

 

[Nick_1987 5.7 OMC]

Well a stretched cable would cause the drive to jump out of gear with a CLUNK, not slippage. If when you lose drive the engine temp started to go up; that’s a sign it’s the coupler because the impeller in the drive turns at the speed of the input shaft. If it’s not spinning at engine crankshaft speed the engine temp will rise. If that didn’t happen more likely to be the prop. If you have a good prop try that & see.
Let’s hope it’s the prop a bad coupler requires an engine pull.

Engine temp did not changed at all, the coupler on the other hand was good as well. I think a spin coupler would probably make noise. There was not weird noises nothing just slipling. No vibration no nothing. I just gave engine throttle and after 12-1500 it would slip. After I’d go under that threshold it was ok and I was able to putt back to dock and slip. So sounds to me like it’s a spun prop hub. But the prop is a pressed in hub not the newer style. I will pick up a prop today and go give it a test.