Need help 1990 70hp Johnson Pro Series 2 stroke

Just spend a lovely $800 bills with a local marine guy to fix my motor which was running like crap.

He drained the gas, cleaned the carbs, set the carbs, set the idle, and replaced 2 electrical boxes
- timing box
- power pack?

he stated i was running on 1 or 2 cylinders

In all, $400 in parts, $400 in labor.

Boat idles and starts great problem is when I accelerate. It will go to 4000 rpm for about 2 seconds then immediately down to 2000 rpm and sound like it is bogging.

Any help or suggestion in what could be happening would be appreciated.

Thanks

Scott

Re: Need help 1990 70hp Johnson Pro Series 2 stroke

The 1990 70hp Johnson has one (1) stator, one (1) timer base, one (1) powerpack, and three (3) coils.

There is no electrical box or anything called a timer box. Impossible for the engine to run on one (1) cylinder.

What is the compression of each cylinder (by number, top is #1). With the spark plugs removed, the spark should jump a 7/16" gap with a strong blue lightning like flame on all cylinders..... a real SNAP! Does it?

S/Plugs should be Champion QL77JC4 plugs, gapped at .030 .

The high speed jets are located in the bottom center of the carburetor float chambers. THey should be manualy cleaned with a piece of single strand steel wire. Solvent very seldom does that job thoroughly.

Check the linkage between the vertical throttle arm and the timer base (spark advance) under the flywheel (possibly jumped out of the socket). Also check the timer base to make sure that it doesn't stick as it gets advanced with the throttle.

You say you paid a repair bill in the amount of $800. If this was recently and this is how the engine runs right off the bat, I'd strongly suggest that you take it back to the fellow that worked on it..... and if he blows you off, take the problem and your receipts etc to small claims court.

Re: Need help 1990 70hp Johnson Pro Series 2 stroke

Thanks - I think he replaced the timer base and power pack. I have the old pieces in my truck. He thought maybe that he used the wrong power pack but I think it is more in the timing.The timer base and power pack was $400, I paid another $400 in labor.

I agree and I am not too thrilled at the moment. I was 7 minutes drive from his shop today with the boat in the water and I had just picked up the boat this morning from his shop and I was hoping he would take the 20 minutes out of the day to actually drive the boat to see / feel what is wrong with the engine.

Well, I hope to get the motor running better, thanks for your suggestion

Scott

Re: Need help 1990 70hp Johnson Pro Series 2 stroke

Does anyone know the correct timer base part number and correct power pak part number?

Marine repair guy put in the following and now he is questioning if he had put in the right part numbers?

Timber base - 582724 $254
Power Pak - 0583748 $153

My engine serial / model number is TJ70TLESF 70hp johnson pro series 2 stroke, 3 cylinder engine.

Re: Need help 1990 70hp Johnson Pro Series 2 stroke

1990 70 hp Evinrude/Johnson

Timer Base = 582724, supersedes up to 583378 (Correct part)

Powerpack = 583748 (Correct part)

Re: Need help 1990 70hp Johnson Pro Series 2 stroke

Thanks Joe - Here is another clue as to what my motor does / does not do:

- Moto will easily rev to 6000 rpm when at the dock and NOT in gear.
- only when I put it in gear, will the motor go to 4000 rpm, then cut down to 2000 rpm.

Also, I would like to remove my VRO pump and simply run pre-mixed 50:1 in the gas tank. Is there a simple way of doing this / a write up on what I need to plug / address when I remove the VRO.

Also, I changed the factory fuel lines since the hoses looked really old but now my straight hoses are not routed very well, seem to kink easy. If I get rid of the VRO, I will have more room to route my hoses correctly, any help would be appreciated.

Thanks
Scott

Re: Need help 1990 70hp Johnson Pro Series 2 stroke

To remove the VRO on that motor is easy
Just plug off the oil intake hose at cowling (where the gas and oil line connect to the side of the engine.) I usually use a stainless bolt with a hose clamp and pump oil into the pump before I cap it off. Then unplug the VRO wires on top of the fuel pump. Your good to go.

I have a few questions for you.
Was the motor running properly earlier this season or was it sitting prior to the work.(what was the reason for the work?)
Did he rebuild the carbs or just clean them by spraying carb cleaner in them while they were still connected to the powerhead?.

You said you just replaced the hoses, Did you check for fuel leaks at your connections Make sure theres no leaks or air getting into the fuel system and kinks are never good.

Do you run a water separator and have you changed out the fuel your using?


It sounds to me like its starving for fuel. Clogged high speed jets or dirty sticking float seats in your carbs would cause this.


-Dano

Re: Need help 1990 70hp Johnson Pro Series 2 stroke

To remove the VRO on that motor is easy.
Just plug off the oil intake hose at cowling (where the gas and oil line connect to the side of the engine.) I usually use a stainless bolt with a hose clamp and pump oil into the pump before I cap it off. Then unplug the VRO wires on top of the fuel pump. Your good to go.

I have a few questions for you.
Was the motor running properly earlier this season or was it sitting prior to the work.(what was the reason for the work?)
Did he rebuild the carbs or just clean them by spraying carb cleaner in them while they were still connected to the powerhead?.

You said you just replaced the hoses, Did you check for fuel leaks at your connections Make sure theres no leaks or air getting into the fuel system and kinks are never good.

Do you run a water separator and have you changed out the fuel your using?


It sounds to me like its starving for fuel. Clogged high speed jets or dirty sticking float seats in your carbs would cause this.


-Dano

Re: Need help 1990 70hp Johnson Pro Series 2 stroke

Scott..... Never race the engine when in neutral. That could set up a runaway engine (seen iti happen) whereas the rpms will continue to increase even if you throw the therottle in the idle position. By the time you figure out how to stop it...... connecting rods will be flying out the side of the engine.

If in gear, the engine will only tuen up (tops) 4000 rpm, either the tachometer is set wrong (should be set on #6), the timing is set wrong, the carburetor butterflies are not opening fully, the prop has excessive pitch, OR something is wrong internally (powerhead).

Cutting back (dropping 2000 rpm) may be that your engine has the S.L.O.W. feature (drops the rpm automatically if the engine gets hot) and that a overheat problem exists, OR a cylinder is losing ignition (spark).

Here's a detailed method of converting to premix.

(VRO Pump Conversion To Straight Fuel Pump)
(J. Reeves)

You can convert the VRO pump into a straight fuel pump, eliminating the oil tank and VRO pump warning system, but retain the overheat warning setup (and fuel restriction warning if so equipped) by doing the following:

1 - Cut and plug the oil line at the engine so that the oil side of the VRO pump will not draw air into its system. Trace the wires from the back of the VRO to its rubber plug (electrical plug) and disconnect it.

2 - Trace the two wires from the oil tank to the engine, disconnect those two wires, then remove them and the oil tank.

3 - Mix the 50/1 oil in the proper amount with whatever quantity fuel you have. Disconnect the fuel line at the engine. Pump the fuel primer bulb until fuel exits that hose with the tint of whatever oil you used. Reconnect the fuel hose.

That's it. If you want to test the heat warning system to ease your mind, have the key in the on position, then ground out the tan heat sensor wire that you'll find protruding from the cylinder head. The warning horn should sound off.


Also, I would like to remove my VRO pump and simply run pre-mixed 50:1 in the gas tank. Is there a simple way of doing this / a write up on what I need to plug / address when I remove the VRO.

Also, I changed the factory fuel lines since the hoses looked really old but now my straight hoses are not routed very well, seem to kink easy. If I get rid of the VRO, I will have more room to route my hoses correctly, any help would be appreciated

Re: Need help 1990 70hp Johnson Pro Series 2 stroke

Thanks for both your responses.

The boat was not run much last year and the year before it did not even go in the water. He did remove the gas in my fuel tank, said it was pretty gunky. I believe also he cleaned the inside of the carbs.

The carbs look clean on the outside and the service guy sales he cleaned them, I do not know if he actually took them off or like you said, just sprayed them.

I got a call from him today and he says it is fixed. He changed out the power pak (AGAIN) and said he re routed the gas lines since they had a kink.

I will know how well the boat runs later this week.

Regarding the RPM, I thought the motor is suppose to turn over 4500 rpm at wot? my tach is on #6 from my memory.

I will let you know how the boat runs.

Scott

Re: Need help 1990 70hp Johnson Pro Series 2 stroke

Scott..... You state "Regarding the RPM, I thought the motor is suppose to turn over 4500 rpm at wot?"

Yes, indeed it is, usually up around 6000 rpm BUT not in neutral!