1983 50hp, choke to keep running.

[JustWarminUp]

1983 50hp Johnson.
Did the Throttle Cam and got it timed up enough to run good enough to single out the last problem.

Dies at mid throttle, and full throttle has a minor surge/lack of power.

Today while it was running, i found that I could bump the Choke and it would immediately clear the stall, and at full throttle if I held it on and off for 2 seconds or so I had full Top end with no surge.

Fuel pump is new and Compression is 130 on both. Fuel lines and prime bulb new, fuel tank good. Carbs done (Twice to make sure).

Is there an passage or something that could be leading to low fuel pressure?

 

[racerone]

Simple fact for you.----The motor respond to CHOKE.------That clearly indicates that you need to revisit carburetor work.----Verify that the high speed jet ( orifice plug ) that is INSIDE the carburetor bowl is clean.

 

[JustWarminUp]

I swear the carbs are done up to near perfection, including new needles and seats floats and all the workings, but for good measure I will go through them again.

I'm wondering if the natural Pumping is being Hindered
The breather tube (possibly called the Gas Recirculation? I just read about this but haven't found more detail other then the name) that comes from the Airbox and goes to the lower part of the intake manifold had some large metal shavings, almost looked as if from when it was made that the hole never got de-burred. the shavings were circular in fashion and would have matched a drill bits channeling if I checked. I sucked them out with a vaccum. And shot some air through to clear it out. I'm wondering if air passages within the motor that drive the fuel pump might have blockages further up I cannot find or I pushed some further in.

 

[racerone]

That hose from the airbox to the block is NOT the recirculation hose.----The recirculation passage way is not visible without removing the intake manifold.

 

[Captain Greg]

if you use ethanol gas you need to clean your carburetors

 

[JustWarminUp]

Okay, that solves that thought. I had no idea if that had any effect. That means it's just a breather hose(right?)

Carbs cleaned again and new fuel hose from tank connection to pump and from pump to carbs and the T's, this weeks goal. We will see what happens.

 

[JustWarminUp]

Same thing is happening, doesnt want to go from idle to WOT without dying after a small increase in throttle, if I hit the choke function it solves the issue and I can go.
my WOT no longer surges or benefits from the choke function, its stable. (Guessing from the bad fuel tank connector, always felt like it had air to purge when firing up at the dock)

Carbs are 100% cleaned, with already previously new kits, new hoses and clamps for the ENTIRE motor. Perfect fits and no kinks.
The fuel tank to motor are 2 brand new brandname Johnson connectors that seal flawlessly. (1 was crappy before, so I bought 3 today and replaced both sides with a spare for future) with already new line and primer ball.
Fuel is new, oil ratio perfect, tank in good shape.
Pump does not leak out the back when removed from the motor and pumping the primer bulb.
Pump was new last year, going to try the old one next time I go out.

Idle also does not benefit from choke function, it just seems to flood out.
But
I might say MAYBE my idle is "Chuggy" BUT it also could just be that it's a 2 stroke from 1983.

New details involve charging? Maybe? I didnt have my voltmeter with me so I didnt have DIRECT battery testing but just my overall basic wiring to my console.
My fish finder doesnt register over 12.4v when the motor is running? Also once started the battery voltage is slow to go from 12.0 -12.4.

 

[racerone]

Fact----Your charging system is NOT WORKING if all you get is 12.4 volts at high RPM.

 

[JustWarminUp]

Could that cause these problems? I have questioned my stator before, but the sparks jumping more than a 1/2 to 3/4inch gap led me to believe it was good.

 

[racerone]

The stator is made up of 2 sets of windings.-----One set to charge the battery through a rectifier.----The other set provides a voltage burst to charge the capacitor in the powerpack ( cd / switch box )----And no the 2 sets of windings do not talk to each other, they are separate.

 

[JustWarminUp]

So my charging is probably weak but that's still not the issue...good god!!!!!!! Why must I be so persistent on fixing things instead of buying a new one!! Lol.

 

[racerone]

If you can solve it with big $$$ then you do not have a problem.----New motors are the best option for many folks.

 

[JustWarminUp]

I wish I had big $$$.

So as I have read, 2 strokes use a rich condition at idle to get their acceleration. Is there a way to increase the richness of my carbs? They are fixed jet, the bowls are definitely not running low on fuel and there is no chance for extra air, and a newer fuel pump turns a starvation to the carbs away in my mind. Unless there is a vaccum leak to pump, but the fact the choke works flawless to solve the problem I doubt it even more.

I also referred to a diagram and confirmed I have the correct jets in the correct spots.

 

[racerone]

What other trouble shooting have you done besides looking at carburetors ??

 

[JustWarminUp]

Tons, I dont even remember where I started at this point. Checked the reeds with a flashlight for bad sealing, OHM checked parts, replaced almost all the electrical other then the stator, new fuel system. Removed the head to check the pistons and make sure there was no water making it's way in. New ignition system again other then stator. Checked grounds, compression ,connections and anything for leaks with starter fluid around gaskets and mounting surfaces.

 

[JustWarminUp]

Followed all torque specs as well, and used exact gaskets with no cheap skating.

 

[JustWarminUp]

I feel there is a timing issue. Joe Reeves method and the motor specific manual got me to this point. Which lead to a better idle and the ability to get WOT. But the mid throttle is still an immediate kill.

Also I had taken the flywheel off at one point to check the stator for physical damage and the flywheel key was healthy with no damage and I returned the stator to the exact mounting I found it.

 

[Crosbyman]

just fyi... been reading up on similar issues posted on utube

oddly...spark plugs seems to be a contributor to "die in mid range and needs a choke burp"
see one comment...
Douglas Helminiak yes I did get it figured out! Something so simple, had mercury spark plugs in it and also top carb gummed up, had it cleaned thoroughly , went to lake past weekend and was fine! So was spark plug change and top carb, so was only running on one carb

anyway read up on comments and replies maybe you can find something