'67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

[BonairII]

Guess I should start a new thread cause my motor isn't bogging anymore, now I can't seem to keep the port side cylinders running.

Quick overview:
Compression is 90psi across the board
Starboard cylinders are running fine (I pulled plugs one at a time and engine stumbles/dies)
Port side cylinders are not getting fuel, i think. Plugs are dry. Pulled plug wire and idled motor...plugs still dry afterward.

Misted starboard carb and motor "poofs" out the exhaust(maybe it's a sneeze, maybe not)
Misted port side carb and engine stumbles and dies

I would assume the port side carb feeds the port bank of cylinders, correct? If this is the case, I have no idea why misting the port carb would stall the motor cause that bank of cylinders isn't running.

Cleaned carb out for the third time yesterday and it ran great. Got boat up to 33mph with lots of low end power. Docked the boat last night and started it today...and the 2 cylinders were not firing AGAIN.

 

[BonairII]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

Anyone? Not sure if I'm asking dumb questions or maybe I have some rare motor that noone here knows how to fix.

 

[BonairII]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

Since, I'm not getting any replies...I guess I'm on my own trying to get this fixed. I took the carbs home again yesterday and poked and prodded every orifice I could find. Hopefully, every passage is clean cause I'm getting tired of pulling the carb off the motor.

Even though, they are normally not the culprit...I'm suspecting that maybe I there's a problem a reed(s) on the port side. I'm going to take a look at them when I go back to the boat. I took off the intake manifold on my parts motor today, so I knew what to expect when I opened up the motor on the boat. I'm actually hoping to find a problem with the reeds cause if it's not them, then I have no idea why my port side cylinders aren't getting fuel.

 

[Borgey401]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

Have you eliminated spark already? I'm not too sure on the background of your motor so I don't know what you've done already. Seems like compression is not an issue considering you've got good, even compression across all cylinders. Another thing did you actually rebuild the carbs or did you just clean them?

 

[BonairII]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

I have spark, but can't seem to get fuel to #2 and #4 cylinders(port bank). In the video I'm misting the carbs. For some reason, the motor bogs down when I mist the port carb. I don't know why it would bog since the port cylinders are NOT getting fuel.

When I mist the starboard carb I get some belching out the upper exhaust (and also out the lower exhaust- watch giant bubbles coming from under water)

I opened the intake manifold and didn't see anything wrong with the reeds(anything obvious anyway).

I even tried spraying fuel into the port cylinders then putting the plugs back in...hoping to 'prime' the cylinders. No luck.
http://www.youtube.com/watch?v=Jd6v7Kx8_ck
http://www.youtube.com/watch?v=-e7l5n80CMU

BTW: I had all 4 cyls running yesterday(after days of work on the motor) . Ran it up and down the river with no probs. Started it the next day....and the 2 cyls were dead again.

 

[Daviet]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

If you keep cleaning the carbs and the problem goes away for awhile, I would wounder if you have a fuel line or something coming apart from the inside and contaminating the carb again.

 

[BonairII]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

Daviet,
It Doesn't go away for awhile. I just happened to get the 2 cylinders working yesterday. I have no idea what made them start working.

Cleaned the heck out of carbs last night...and still no fuel to #2 and #4 today. Checked fuel line connections for leaks. Made sure carb was tight.

Do u have any idea why the port side carb bogs when I mist it? those are the cylinders that AREN"T getting fuel...shouldn't misting that carb feed the 2 dead cyls?

The other day I swapped carbs from my parts motor and still no fuel to cyls 2 and 4, so I've got to believe it's NOT a carb issue. I also ran the motor for 10 seconds with #2 plug wire off and the plug wasn't wet when I pulled it.

 

[Daviet]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

Just some thoughts. You have good compression on all cylinders. The spark will jump a 3/8" air gap and is bright blue (don't have 2 & 4 plug wires crossed?). Are #2 & #4 plug wires touching togeather, maybe arching to each other? The only thing left to make your engine run is fuel delivery and timing. The timing should be good because it did run properly before. It does sound like a fuel delivery problem, but I can't figure out the not firing when you spray fuel into the carb.
When you cleaned the carb did you completely disassemble the carb and soak it in cleaner and blow it out with compressed air?

 

[BonairII]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

I don't believe #2 and 4 are crossed. The plug should have been wet when I let it run without a wire attached, correct?

I completely disassembled the carb, pulled jets/nozzles, float seat etc etc. I ran fine wire into every hole/orifice. No compressed air, so I blew passages clean by mouth(i used a snorkle tube).

 

[Daviet]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

I have to think on this one for awhile, maybe look at a manual. I'll have to dig up a manual and get back to you.

 

[BonairII]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

I'm pulling my hair out. I'm at a loss right now. I pulled the boat today and brought it home. Gonna fiddle some more with it tomorrow.

 

[yorab]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

Did you use a venturi locating tool when replacing the venturis? I've always been under the impression that "close enough" is good enough when replacing the venturis but Joe Reeves and FR both said that the venturis need to be located with the tool. I took their advice and bought the tool from FR who machines them himself.

 

[BonairII]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

Replace the venturis? Why would I replace them? They simply bolt-on, no adjustment possible to my knowldege.

 

[yorab]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

The high-speed tubes are located under those venturis. Your problem doesn't seem like a high-speed-circuit problem, but it is best to clean all passageways when cleaning the carb--it definitely removes variables from the problem.

Let me think about this a bit more and I'll try to help with appropriate suggestions...

 

[BonairII]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

I pulled off the carb AGAIN today. I cleaned the passageway on the top edge of the intake flange again(that mates with the carb). I did find a little brown stuff when I sprayed carb cleaner, but it didn't seem to serious. I pulled the intake manifold completely off and checked the passages behind the gasket...all clear.

I shined a flashlight on the reeds again...nothing. I was tempted to pull off the reed housing and check them with a flashlight(in the dark), but the screws wouldn't budge and I was too afraid to go any further. I'd really like to pull out the reed housing just to I can completely rule out a reed problem. Anyone know if I would need new gaskets if I pull the reed assembly to inspect it?

All fuel lines are brand new and I have hose clamps on all lines to make sure there are no air leaks. I put it all back together and the motor started right up, but as usual NO FUEL TO PORT CYLINDERS

What else could be causing no fuel to port side?

Tomorrow I'm going to pull all plugs and have my son turn the motor over while I hold paper over the plug holes just to make absolutely sure that the port side cylinders are indeed starved of fuel. I'm also going to drape a dollar bill over the port carb while the motor is running and see if air is being sucked in or pushed back ( I read this trick here).

I'm running out of things to check.

 

[yorab]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

You will need gaskets if you pull the reed boxes. There are two of them. Most parts guys should have those gaskets. If it were me, I'd check for mist at the cylinders first. Then, if it were starved of fuel, I'd pull the reed boxes to check things out. If it turns out that it is not starved of fuel, it still could be an ignition issue. When checking for spark, most people just look for one or two blue arcs then assume that spark is okay. But the spark needs to be not only strong but also consistent. So perhaps (and this is grasping for a solution) you have an issue with spark consistency. Anybody who has dealt with electrical issues has probably seen some funny things happen. Electrical issues can manifest themselves as a percieved pattern, when in actuality the problem is more random than one may think. When electrical components begin to fail, they can behave poorly the first day, work perfectly fine the next day and then not so good the next. The troubleshooter then finds himself ruling out the possibility of bad electrical components because "it worked fine yesterday". This happens quite often with loose (but not too loose) ground connections.

Again, I'm just trying to bring up some things for you to mull over. I'm certainly not suggesting to replace parts at random. There is a logical solution to your problem and it will eventually be found. Hopefully, you'll still have some hair left once you figure it out. But start with the fuel mist test.

 

[AlTn]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

I'm with yorab on this...when it's running can you put an inductive timing light p/u on each sparkplug lead and confirm or condemn each cylinder for consistent and strong spark?

 

[BonairII]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

Assuming I borrow(buy) a timing light, how do I use it to check for consistent spark? A timing light will work better than an adjustable spark tester?

 

[Daviet]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

Just clip the lead over the plug wire while the engine is running, if the light flashes you have spark on the wire. A timing light will allow you to check the spark while the engine is under load and under any running conditions.

 

[BonairII]

Re: '67 Johnson 80hp. Dropped 2 cylinders.....AGAIN!

A timing light will allow you to check the spark while the engine is under load

Unfortunately, I can't check it under load cause the boat is in my driveway. I'll have to see if my neighbor has a timing light. Going to check again with spark tester in the next 30mins, and also for presence of fuel to the #2 and #4 cylinders.

I have an update shortly.