1984 Johnson 40hp...won't go fast

[dfrants]

Got a 1984 Johnson 40hp tiller model E40TELCR, don't know why it has an "E" instead of a "J", but it is a Johnson. This is the two cylinder two carb model. She starts quick and easy. Idles ok...not as smooth as it should, has great compression 145# top 140# bottom, but when you give 'er gas she won't plan off the 16' lund she's on. I pulled the carbs and made sure all the jets and passages were clean, tried to different fuel tanks and made sure both cylinders have spark. Still no luck. Any ideas? thanx.

 

[Silvertip]

Was the engine working fine before this? If this engine is new to you then remove the air box and look at the throttle plates in the carbs as you move the throttle full open. It may be the cable and/or linkage needs adjusting. The throttle plates should sit perfectly horizontal when the throttle is wide open. NO! The engine does not need to be running to do this check.

 

[dfrants]

Last year she ran fine, full speed and idle. just double checked the throttle plates and they open fully. Checked the timing plate to see that its not sticking. Also checked the gear lube and that looks clean also.

 

[racerone]

Flywheel key ?

 

[dfrants]

Haven't got the flywheel off yet to check the key...but i removed the carbs and the spark plugs. When i turn the flywheel i can hear air and see fuel bubbles in the top cylinder reed cage. Kind of a guargling sound. Is this normal? I don't see it in the bottom one.

 

[dfrants]

Question #2...when i turn the flywheel a full rotation, i can see the timing plate move a nudge, like something is rubbing against it for a second. should this be happening???

 

[oldboat1]

Yes on Q.1. Need better explanation on Q.2**.

Check the linkage and cable as suggested, along with the flywheel. If the flywheel hasn't moved/key not sheared, and controls/linkage not an issue, I would suggest removal and full cleaning of carbs. Measure spark with an open air tester -- half inch or more to insure sufficient output. Motor has to spin over at 200+ rpm to start.

[edit. **e.g., know if the stator or charge coil was replaced? (flywheel binding for insufficient air gap.)]

 

[dfrants]

I don't if the stator or charge coil have ever been replaced, but something under the flywheel is causing the timer linkage/base to slightly move like its getting rubbed against when the flywheel is turned.

 

[racerone]

There are very strong magnets in the flywheel.-----They pull on parts under the flywheel.-----I doubt anything is rubbing in there.

 

[juno pierrat]

this sounds like a problem that a utuber just fixed on "this old outboard" channel. but on a 25hp. its always very backyard fix-it stuff, look at " Evinrude 25 Hp 1989 - Its Mind Boggling"and "Evinrude 25 Hp Armature Plate, Support, Bearing, Retainer FIX !"(about 3 months ago) may be helpfull, hes a little hard to watch, but gets-hrr-done!

 

[dfrants]

Thats what my motor is doing only not as bad.

 

[dfrants]

Removed the flywheel and found that the charging coil must have got very hot and leaked black sticky liquid onto the ignition plate. Would a "bad" charging coil cause a motor to only run at half speed?

 

[juno pierrat]

Yep, ruff idle , only about 1500 to 1800 rpm's, happened to me on a 48spl

 

[dfrants]

Replaced the charging coil...idles alittle better but still won't go fast. Retested the compression and the top cylinder is at 150lbs! Botton 145lbs.

 

[juno pierrat]

do a open air spark test, should jump 1/2" as suggested before. also do a drop test, see if both cylinders are firing

 

[dfrants]

not getting a good strong blue snap spark...after turning over 4 or 5 times it will spark a light weak one.

 

[juno pierrat]

good compresion numbers, electrical troubleshooting, use this site http://www.cdielectronics.com/troubleshootingguide/mbers

 

[oldboat1]

not getting a good strong blue snap spark...after turning over 4 or 5 times it will spark a light weak one.

Sounds to me like it might not be cranking fast enough. Jump the starter directly from your car or truck with a good set of jumpers -- direct to starter (pos. to post on starter, neg. to starter mount). If it clearly turns faster that way, you have an electrical issue somewhere -- maybe just corroded connections. Maybe a bad battery. Can test spark that way, but probably need an extra pair of hands.

 

[dfrants]

ok...cleaned the leads, got a new fully charged battery and retested. At 1/4" gap I get a strong blue spark, at 7/16" nothing. Does this look like a stator issue?

 

[oldboat1]

If spark now has a sharp snap, think I would try it in a barrel or on the lake -- see what you have based on what you have done so far.