1993? Johnson 70 HP 3 Cylinder 2 Stroke - Stalling Issues

[70JohnsonNH]

Hello all,

Is anyone familiar with with this Johnson motor? I am having trouble with it not being able to idle or be at a low RPM. Unfortunately my tachometer is busted and I cant tell where the minimum RPM is before it stalls. I do know where it is on the throttle though.

I'm not trying to around the lake. The problem is when I am trying to dock it becomes very difficult and sometimes dangerous if its windy enough.

I'm not sure the lingo for some of this so I'll try to describe it the best I can.

for me to cold start the motor I have to push a rectangular button on the throttle, put the throttle in gear and keep "pumping" (aggressively pushing it forward and back, not getting back into the neutral position) the throttle while I turn the key until it turns over. Some times this takes 2 or 3 times before the engine starts. Then I lower the throttle to the sweet spot so it doesn't stall.

when the throttle is in the true neutral position the motor will 100% stall. the throttle has to be in gear and pushed forward probably about 1/2 inch or so for it to continue to run. at this position the boat is moving at a pretty good rate which is fine until I am trying to dock. what I'm always worried about is it stalling and then not being able to start it quick enough to hit a dock or another boat.

Long story short, I am wondering if there is an adjustment that can be made so it will idle in the neutral position. I previously had a Johnson 2 cylinder 2 stroke that would idle no problem so I figure these types of motors have the capability to do so?

 

[racerone]

Stop pumping the throttle lever as it does NOTHING to help start a cold motor----Are you pushing the key in and holding it in while cranking for cold starting ?----Start the trouble shooting by posting the actual compression test values.----There have been issues with #2 cylinder scoring.----Running with tested VRO mixer or mixing oil and gasoline 50:1 in the tank?----There was a service bulletin in 1994 to move the telltale hose to the top of the block.----Your motor has not had that simple procedure done !

 

[70JohnsonNH]

I bought this motor from a marina/mechanic. I was told they had it apart to repair the water pump and gaskets before it was sold to me and that it had passed compression tests and everything was working as it should. The only thing I was warned about was to not use ethanol fuel as these older motors and their components aren't designed to withstand ethanol

With that being said.. I've had this stalling issue since day one. I brought it to their attention and they had a mechanic come to me to do a ride along to see what exactly the problem was. They showed me how to start the motor by pumping the throttle leaver. I was also told there could be no delay in changing gears. I had to do it fast. because if I let the RPM get too low near neutral it would stall.

- I have tried pushing the key in / choking while cold starting. but again, while in neutral the engine will not run so it doesnt turn over.

- I have not done a compression test myself but I will try to get it done tomorrow.

- The pictured oil system was installed with this motor, replacing an old one that I have for my previous 50HP Johnson.

- I did not know about the telltale needing to be relocated. I will look into getting this done.

 

[racerone]

Pumping the throttle lever does NOTHING.--There are no accelerator pumps in the carburetors.---Your shop is not doing you a favor .----Pumping the main lever may in fact damage the control box / cables.----Raise the idle lever.----Push key in and hold it in while cranking the motor over for cold starting.---Post the actual compression values here.-----Perhaps find another shop.----Test that VRO unit per a manual.----Or mix at 50:1 while you determine that VRO is injecting the correct amount of oil.

 

[70JohnsonNH]

Is the idle lever in one of the pictures I posed? I will try that tomorrow and see what happens

 

[racerone]

It is on the control box.----Post a picture of your throttle / shift control box.

 

[racerone]

Then again you may just need to adjust the idle speed stop screw.----Perhaps it is idling too slow.

 

[Vargrklaw]

This may not be related to the issue, but when you say the engine won't turn over in neutral, maybe an issue with the neutral safety potentially causing the stalling issue? Maybe grounding out spark when it shouldn't....But I agree with Racerone, it sounds like your idle speed it too low in neutral, then it drops even lower in gear and the engine stalls.

You need a tachometer, and a better mechanic that knows what they're talking about. Racerone has imparted lots of knowledge on many people here, including myself Listen

 

[racerone]

Maybe you do not have the typical Jonson control box.---Pictures are needed.----And a better shop to help you !

 

[70JohnsonNH]

pictures of compression test and throttle

 

[racerone]

I assume pushing that black button disengages the shift function.----The lever is then " throttle only"----Pumping that lever does nothing to help start this motor.

 

[70JohnsonNH]

Is the compression good for this motor? I saw they should be within 10% of each other and they’re all spot on

 

[Droid]

This may not be related to the issue, but when you say the engine won't turn over in neutral, maybe an issue with the neutral safety potentially causing the stalling issue? Maybe grounding out spark when it shouldn't....But I agree with Racerone, it sounds like your idle speed it too low in neutral, then it drops even lower in gear and the engine stalls.

You need a tachometer, and a better mechanic that knows what they're talking about. Racerone has imparted lots of knowledge on many people here, including myself Listen

Neutral safety switch is in the yellow/red wires and only disconnects the start function of the key switch from the starter solenoid. It has nothing to do with engine operation.

 

[70JohnsonNH]

Could it be a carb adjustment screw issue? They all seem to be in different positions