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1982 70HP Johnson -Carb blocked

P

patiolatern

Regular Contributor
Motor runs great until it bogs down trying to get to higher speed.
Speculated it’s debris in carb somewhere so took a look at carb drain and idle jets. Found blockage in bottom one, cleaned and
put back together. Ran great. Same thing a happened a few days later.
New fuel filter on engine and new fuel lines from tank to engine.

I don’t know if the motor has had fuel lines replaced. Can you tell from the picture? Where else could these particles to clog the jets be coming from?

thanks!
 

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I was told the grey line from tank to motor is new and the drop cylinder
test may help identify the blocked carb but I really want to know is
if the motor’s fuel lines are original or not. Where else could debris be coming from to blog the fuel a little.
I guess even if the fuel li we have been changed at some point I will probably change them just so that is done.
any other ideas?
 
Do not run this motor until you have this debris issue solved.-----A blocked carburetor ( no oil ) can destroy the motor !!
 
racerone said:
Do not run this motor until you have this debris issue solved.-----A blocked carburetor ( no oil ) can destroy the motor !!
Click to expand...

Thanks and will certainly take that advice!!

I took a look at the fuel pump and filter and the filter part just looks like a mesh screen but everything looked clean. Sampled a little of the fuel going in and looked clean.
I then took off the fuel line coming off the pump and it was disintegrating as I touched it. Sampled this fuel and it was dirty(lot of particles). So….. this week I will change out the motor’s fuel lines from pump on in.

Can anyone confirm the size of fuel line?
Looks like 3/8 ID from pump to first connection and then maybe
1/4”ID after that to carbs?

FYI the fuel tank is almost new and the fuel line from tank to motor looks new and shows no sign of age or delaminating. I took off a connector to check.


I will run the 9.9 kicker in the meantime


thx
 
patiolatern said:
Will do!

You have any knowledge of a trim seal kit for this motor?
my left hand side cylinder leaks a bit. Probably going to need the tool to tighten cap as well.

Model J70TLCNB
Serial # C8159844

thx
Click to expand...

All the lines have been changed and fuel drained from the carbs.
Looked like two of the carbs had debris. Drained them a couple times, blew them out with air and then filled with fuel. I will check them tomorrow just to have a look and then test out and they are clean then will take it out to test on the water.
 
patiolatern said:
All the lines have been changed and fuel drained from the carbs.
Looked like two of the carbs had debris. Drained them a couple times, blew them out with air and then filled with fuel. I will check them tomorrow just to have a look and then test out and they are clean then will take it out to test on the water.
Click to expand...

Ran the motor today and it ran great at both idle and full throttle. Stopped and did some fishing for 30 minutes or so.
Started it up and when I went for more power it bogged down again. Did a simple clean of the carb and it went back to working at high speeds. Had to do this a couple of times but the last time I was not able to get high speed. Pulled the boat off the water and figure my next step is to pull all 3 carbs clean and rebuild them.
Maybe I could have saved some frustration if I had just did this from the start….don’t know.
I will order the carb kits but any tips on the disassembly process for all the linkage?
Does this mean when I reassemble the three carbs I will have to do a resync of the engine or maybe not?
 
Update: This is a little long winded so thanks for reading and helping!

Rebuilt the carbs and reinstalled. Not a very difficult process and installation seemed to be identical to original.
Took it down to the water and tried to run. Started and ran but did not want to accelerate. Took it back to the dock and removed the air inlet cover and just stared at the motor while idling....I must have scared it because I could feel it wanted to accelerate. Pulled away from the dock and it ran like great. Ran it for 30 minutes and tried to simulate the issues I had. went slow for 15 Min and it accelerated fine. Stopped for 15 min and it accelerated fine.
Thought I might be done....Took it home and put the air cover on and put it away for a week.

Took it out today and same thing....would not accelerate.
We docked the boat and I took the air cover off again....Acceleration came back and ran great.

Open to ideas?Update:
Rebuilt the carbs and reinstalled. Not a very difficult process and installation seemed to be identical to original.
Took it down to the water and tried to run. Started and ran but did not want to accelerate. Took it back to the dock and removed the air inlet cover and just stared at the motor while idling....I must have scared it because I could feel it wanted to accelerate. Pulled away from the dock and it ran like great. Ran it for 30 minutes and tried to simulate the issues I had. went slow for 15 Min and it accelerated fine. Stopped for 15 min and it accelerated fine.
Thought I might be done....Took it home and put the air cover on and put it away for a week.

Took it out today and same thing....would not accelerate.

Open to any input or ideas...

One thing I wanted to check on was the choke plate and primer solenoid.

When I press in the ignition in to activate the choke it closes the plate by about 2/3 but it does not go back to a fully open position after release.
I only noticed this because I removed the air cover and tested the choke.
Since I tend to use the choke when I first start the motor I wonder if this is affecting acceleration....when I have issues I take off the air cover and probably(maybe... I don't know for sure) open the plate manually which solves the acceleration issue since I don't need the choke at this point it leaves the plate fully open.

The question is how far should the choke close the plate on carb and should it revert back to the level position?
Is there any maintenance I can do on the Solenoid assembly?
Is there any test I can do on the Solenoid? The manual does not indicate the Ohms for this 1982 70HP Johnson.

Thanks!

Additional info:
Fuel pump was checked out and looks perfect
Checked temp of cylinders and all three were the same-not hot
Checked for TDC and pointer lined up perfectly
Used timing light and at idle it was per spec indicating TDC.
 
These have a " mysterious " spring designed to keep chole plates from fluttering at full throttle.----Perhaps it has been messed with ?
 
Took the solenoid apart along with the spring to choke plate linkage. Cleaned everything and put it back together. Overall everything looked good.
I was able to now see the choke plate close completely when choke on ignition activated.
The choke plate does not reset itself back to open. It looks like it wants to but not enough force to push the linkage to the open position.

I have tried adjusting the solenoid's position but with no improvement.
The spring inside the solenoid does not seem strong enough to push the plunger and external spring to move the linkages. The external spring does flex when ignition choke is released but that's it.

Even moving the plunger by hand to open the choke plate takes a little bit of energy.

I ASSUME the spring internal to the solenoid has lost some of it's life....

Any tips to get the spring out of the solenoid? It's kind of trapped by the key for the plunger.
Any way to measure the spring strength as to what is NORMAL?

Thanks.
 
Well the story ends!! Motor ran great today!! Thanks to everyone's help especially raceone!

I took the solenoid off and removed the internal spring and cleaned everything up. The internal spring seemed really weak so I thought I would end up buying replacement springs...maybe used ones since shipping to Canada from ebay is horrible most of the time.

The internal spring on ebay looked weak and identical to what I had.

Slept on it....

Went back out this morning and started to look at the setup a little more.
When looking at the linkage connections I had put grease on the white fittings that hold the connecting rods. The grease was there before I rebuilt the carbs so after I just put the new grease back.
As I move the linkages manually I started to focus on each connecting location. I removed ay visible grease and cleaned each connection.

I sprayed silicone Grease and moved each one around to see how the friction was. The bottom one was a little tougher to move so I took this one out and lightly sanded it. Spayed a little lube on it. I reassembled the linkages and everything was perfect. The choke plate reset just on it's own. I have reassembled the solenoid and everything stayed very loose.

Took it out with 99% confidence and I was rewarded with a great ride!!

THANKS!
 
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