1981 Johnson Evinrude not achieving WOT

[J140TLCIH]

Hello. First time posting. I have a 1981 J140TLCIH that was going WOT about 29mph acoeding to GPS, (no tachometer) i slowed down put it in neutral shut the engine off fish for about 15 minutes. I start the engine up put it in gear and it wil not go but maybe 7mph. I slowed down put it in Neutral shut it off. I start it again pushed the throttle as far as it will go and it sounds like the RPMs are up there but its not going to WOT. Also regardless of trim tilt position.
At home i took the cover off check the throttle from end to end of linkage, fuel lines, spark pluggs wires and pluggs, fuel primer bulb and all the wiring that i could see and thought might be associated with this issue. It all checked out at a glance. I hooked the muffs to lower unit made sure water is going full pressure, squeezed the fuel primer untill it felt firm, primed the cylinder a few time and started the engine. I should mention i usually give it a little throttle to start it. Makes it easier. Also usually lay on the primer solenoid (push in on the key) intermittently untill it gets up in the rpms then i immediately bring the throttle down to iddle as low as it can without dying. It acted as usual. I bought some seafoam and ran it for 15 minutes at iddle and i gave it a little throttle but not much because im not sure its good to do on muffs. Went back to the lake and the same thing hapened. After many web searches, some volt meter test, i changed out 4 coils, 4 spark plugs(0.030) and wires both to plugs and coils,cleaned the grounds and replaced the battery cables, ignition switch cables, starter relay and starter motor. Tore the carbs apart multiple times and cleaned them. Ended up buying two refurbished carbs fom the web. Took the new carbs apart and corrected some issues. Also replace water impeller and installed both thermostats and check valves (it had neither). Checked for spark by lifting the boot and watching for the arch and they all did. Took it back to lake and same issue. I push the throttle lever to WOT but it only goes about 7 mph according to GPS. I bought a SELOC repair manual. According to the trouble shooting by symptom guide (powerhead fails to achieve WOT) it could be restricted fuel supply to powerhead, VRO or fuel pump malfunction, gummed or dirty carbs or broken or bent reed valves. I dont know much about engines but what i find on the web and read in the repair manual. Sorry for the long write up. Any thoughts.

 

[interalian]

Start with a compression check. This one should be 125+ per hole.

Next would be a cylinder drop test when it's acting up.

What boat do you have? Weight? How long have you had the motor. Is this new behavior?

Oh, and revving in neutral is a bad idea and won't prove the motor is working properly.

 

[J140TLCIH]

Thanks for the quick response interalian. I will be trying what you suggested. Thanks for the info about not going WOT in neutral. The boat according to the previous owner is a 17ft 1970 Chrysler not sure on the model as i can not find a HIN. The previous owner said it was pre year which i guess means it was not requiered or something. Not sure if this is right but it might be a hydra vee. The original outboard was a chrysler 70 hp that was not supposed to work. Somehow i got it to run good enough to leave me stranded in the middle of the lake. Scrapped that motor after sinking a few bucks in. I traded a motorcycle for the current 140hp. I've had it for about a year. The first thing that went out was the starter, then the solenoid, then a coil. Then this. As far as weight not sure but what ever the weight of the boat is it has 400 lbs of sand bags and a 26gl aluminium fuel tank as far up front as i could to compensate for the 140hp in the back plus 2, 15 gal tanks one on each side. Its got 2 steering wheels im usually outback so i can stand the other is up front. Im sure im over weight but its never been an issue. At first i thought i was the new fuel tank but after changing carbs and adding filters i didnt think it could be. Also i was out the day before it did this to test the balance fully loaded and it was fine. It always took a bit to plane out even when it was just me and a 6 gal fuel tank. So i knew with all that weight it would take even longer but it did it. Again thanks for the help and i will do what you suggested when i get the tools.

 

[racerone]

Post the compression numbers.----These motors have a habit of breaking piston rings.

 

[interalian]

Cripes, between ballast and a full fuel load, you're carrying 625lb before passengers!

Post back often, and send pictures. We like pictures.

 

[interalian]

BTW, re-reading your first post (kinda hard due to no paragraphs, sorry), you seem to say you had the throttle wide open and the revs were up but it was going 7mph. If that's the case, your problem is a slipping prop hub. Please clarify if this is an accurate interpretation.

""I start it again pushed the throttle as far as it will go and it sounds like the RPMs are up there but its not going to WOT.""

Oh, and the Seloc manual isn't too good. If you plan to keep the motor, find an original OMC Service Manual. Usually ePrey is a good source.

 

[J140TLCIH]

Racerone i will post the results as soon i i do the test.
Interalian, sorry for the poor grammar comp. I don't think the prop slipping. Outside of the water i put the motor in gear and i can turn the flywheel by turning the prop. Not sure if thats a good test but is the only one i know. I also pulled the prop and checked the splines and they look ok. In neutral and in gear the motor sounds and performs, but will not in gear or neutral achieve full rpms. Oh and as far as the weight, its the only way to balance that thing and make a 70 mile round trip. Again sorry for the crap grammar and thanks for the help.

 

[J140TLCIH]

I cant upload pics from my phone for some reason.

 

[oldboat1]

compression and spark tests/cylinder drop, as suggested (try a timing light when it's acting up out on the lake -- no flash, no spark).

(Have you tried going back to a portable tank to test fuel supply? Have to think there could be a flow or venting issue with the main system. Must have a selector switch to divert from one tank to another -- maybe an issue with that. Or perhaps a filter system blocking flow? Gotta think it would be running rough if a fuel issue, but worth checking given your unique setup.)

 

[J140TLCIH]

Oldboat1 thanks for the info. Ill do all the test that do not requiere money and will post the results. Waiting on payday to get the tools for the other test. Thanks to everyone. I greatly apreciate the info. And i again apologize for the bad grammar.

 

[Chinewalker]

Not super familiar with your boat, but I would think a 140 on a 17-footer would do a fair bit more than 29mph. I have an 18foot Starcraft fiberglass runabout and it does nearly 40 with my 90 Johnson. It'll even go over 30 with full load of family and dog (6 people and 75 lb. mutt). A full physical on that motor sound like it is in order. A tach might help you, too...

 

[J140TLCIH]

I agree with you chinewalker on the complete teardown. I thought the speed seemed slow but thats how it always ran. i have a lot of of weight on that boat so it can balance, i thought that might be the reason.
Ps. For those who want to see the boat im going to have to do a link to youtube or something. I apologize for the inconvenience.

 

[interalian]

Racerone i will post the results as soon i i do the test.
Interalian, sorry for the poor grammar comp. I don't think the prop slipping. Outside of the water i put the motor in gear and i can turn the flywheel by turning the prop. Not sure if thats a good test but is the only one i know. I also pulled the prop and checked the splines and they look ok. In neutral and in gear the motor sounds and performs, but will not in gear or neutral achieve full rpms. Oh and as far as the weight, its the only way to balance that thing and make a 70 mile round trip. Again sorry for the crap grammar and thanks for the help.

You can check for prop slip by marking the nut and a spot on the prop body, then go for a run. If the marks aren't aligned afterward, it's slipping. Being able to turn the motor using the prop isn't a good test as you can't put nearly the torque on the hub that the motor can. I was basing slippage on reading the post as you said the RPMs were 'up there' but you weren't going fast.

Still, do all the other test, and I agree with chine - the boat should do better than 29 with 140hp.

 

[cfauvel]

interalian has pointed out a great point....when the throttle was all the way down, DID the rpms shoot to 5000-6000 rpms but only went 7 mph?

OR

when the throttle was mashed down, you only had 2000-2500 rpms, but can't tell because you don't have a tach, and was only doing 7 mph.

surely you know the difference between 2500 and 5000 rpms by the sound.. Please get a tach on there .

and do the compression test ( I think Joe Reeves has a sticky on proper way to do compression test to get repeatable results)

BUT here is my gut thoughts

1 - if you ARE getting high rpms but no speed, then I think you spun a hub....and others have indicated a way to test that.

2 - if you are ONLY getting 2000-2500 rpms and no speed, AND it was going like gang busters previously, then I am going to suspect the stator or loose magnets....BUT that is going to require a multimeter and a DVA adapter , and jumper wires to properly test......DO NOT throw money away replacing parts willy nilly.


ALSO test with either an external tank or a tank that you KNOW has no fuel obstruction and no gunk in it...

 

[J140TLCIH]

I just did the drop test. First i dropped it from 4ft then 8ft and it just kept going down the cliff. Ha ha ha. It all checked out on the drop test. Snap crackled and popped. I layed on the fuel primer bulb hard and saw a blast of fuel from the upper carb fuel supply hose. Im going to switch the lines again and will post what happens. Thanks to all for the tips and info.

 

[J140TLCIH]

I just posted the YouTube link hope yall can see it. Heads up its a P.O.S. It originally did not have the cab or the wooden monstrosity in the back. I added those because it rains alot in the PNW. Any ways there it is.

 

[J140TLCIH]

Cfauvel. I just saw your post. The rpms are going up but not as it used to. As far as all the parts i changed, I've meant to replace since i got the outboard, but like the saying goes, if its not broken dont touch it fix it. I come to learn thats not a good moto for outboards. When i did the drop test i used a new fuel tank with fresh fuel and ran it at iddle for 15 minutes before doing the drop test. I want to do a complete overhaul on this motor but when you see the boat its on you will see why im hesitant. Now that i saw that fuel leak i wonder if this has all been a simple issue of air getting sucked in the upper carb fuel supply hose. Again thanks to all and if i miss ur post please excuse me my phone is having issues with this forum site. It wont let me see new messages and other issues. Only way i can see the message is by going into the thread and scrolling all the way down. Sometimes it gives me an error when posting and deletes all the stuff i just wrote. So please bear with me.

 

[J140TLCIH]

Just changed the fuel line that was leaking. It starts easier, runs better on muffs/plastic tote and iddles better. Still want to do a cylinder compression test and a timing light test for spark timing. I also want to test and eventually buy new power packs since its probably a matter of time till they go. I suppose i should just do a complete rebuild. I plan on doin a lake test soon. Will post results. Thanks everyone for your help.

 

[interalian]

For power packs, my mantra is to carry a working spare and let them be. I also carry a spare coil. I also carry plugs and a selection of tools, a timing light and a cheap multimeter, all in a US Army surplus ammo box.

Fixing leaking lines is a good call, but any leak between the pump and carbs would just be a leak, not cause a dry carb. Air leaks between the tanks and pump inlet can cause lack of suction and an overall inability to pump fuel. You'd probably see leaks when squeezing the primer ball firmly. O-ring on the quick connect at the motor, or any joints in the hoses either side.

Just a note on running in that tub. If you have muffs and are pressurizing with the garden hose, that's fine, but if you are trying to run just in water, know the pump isn't self-priming and needs to be submerged in water. A good guidline for this motor would be to have the water at the middle of the side motor mounts on the leg, 2" above the joint where the gearcase attaches. I use a 55gal plastic drum I picked up for $15 that used to have chlorine in it.

http://smg.photobucket.com/user/inte...cdell.jpg.html
http://smg.photobucket.com/user/interalian/media/IMG_0767_zpsixryzzx5.jpg.html

 

[oldboat1]

Very interesting hull make over! It looks very similar to a '54 Trojan Sea Breeze cruiser I had (20' outboard cruiser). Just for grins, you might google for pics of a Trojan of that era.

Got a little bit of weight there, but should get a comfortable cruise on plane, seems to me. Does sound like a prop hub issue.