# 1988 Johnson 15hp no idle



## Busbey (Jul 11, 2011)

only way to get it started is to spray starter fluid in the carb, full choke and 60% throttle. from there it sounds fine but will die and need to repeat previous steps to start bad up. also, we are not too sure how to adjust the low speed knob. how many 1/2 turns or full turns out from completely shut/tight until it reaches the proper point where you have that fine adjustment?

i know this is sort of a half arse explanation of whats going on but im sure someone out there can help me out.


----------



## crazymanme2 (Jul 11, 2011)

Don't use starter fluid on a 2 stroke.Good way to ruin a good motor.

I believe the idle screw is 1 1/2 turns out.

Sure your fuel pump is pumping & is choke working?(butterfly closed)


----------



## Pappy (Jul 11, 2011)

Am suspecting the carb needs a good cleaning from the description but how about we start with a little more information such as how long has the engine sat without running? Is the fuel any good, does it have water in it, etc. Then we can give you a better answer rather that several guesses.


----------



## Busbey (Jul 11, 2011)

Just got it. Sat for a year. New gas mixed 50/50.


----------



## Pappy (Jul 12, 2011)

Rather than chance running the engine lean on fuel and oil, get a new kit and clean up the carb and install the new kit. That should solve your issue. Leaving an engine for a year, possibly with fuel in it, is not good with today's gasoline. And no, Seafoam will not clean it up without disassembly and proper cleaning. You can start your initial adjustment of the low speed needle at 1.5 turns and turn it in slowly until the engine speeds up and eventually lean spits then back it back out 1/4 turn and leave it. Thats a good ballpark adjustment.


----------



## Busbey (Jul 12, 2011)

here are 2 kits i found. would one be better than the other? $1 difference and around 15 bucks each. 

Sierra






Mallory





but if all gaskets look good, could the problem be the jets just clogged? short of taking everything apart, is there any luck to be found with just soaking the carb? unfortunately i will not be the one doing this rebuild, a good friend is helping me. just want to make it as easy as possible for him. but if i need to do this, that it is what it is. im just looking for knowledge along with the best solution.


----------



## cajuncook1 (Jul 12, 2011)

I would go with the Sierra kit, because it has everything the Mallory kit has plus it has the float needle clip, which helps prevent the float needle from getting stuck. I didn't see the float needle clip in the Mallory kit.


Pappy, is speaking the gospel here. Don't take short cuts when it comes to cleaning your carburetor, you will enjoy good running and low idling. I have a 1984 Evinrude 15hp and she runs great and idles wonderfully. So, you have a very well built motor and will give you years of good service if you treat her right. That starts with a good clean up with your carb.

Here is a link to a good set of articles related specifically to your motor. The author did a wonderful job of putting all that information together. It will help you maintain and even do some repairs if needed.

https://www.sschapterpsa.com/ramblings/OMC/OMC%20info.htm


Here is a link with a parts diagrams and you can order stuff from them as well. 

https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1988&hp=15


*Be careful, if you soak your carburetor.* Remove all the plastic or rubber parts, the carburetor cleaner will dissolve and eat up plastic and rubber pieces. **Your carburetor may have a black plastic bowl type so, be very careful!!!***

Oh, by the way your fuel to oil ratio is 50:1 mixture. That is 16 ounce of TWC-3 marine 2cycle 
oil to 6 gallons of fresh 87 octane unleaded fuel!!


----------



## Busbey (Jul 12, 2011)

ill go through this info you sent the links for. thanks a bunch. 

quick question about the shaft length.. its a long shaft and looks to have been added on. i assume i will need about 200 bucks to turn this into a short shaft? whats the chances of me adding some sort of extension on my transom to add 5 inches? maybe a 4x4 and big c shaped aluminum piece over front and back of it? im sure there are many ideas and ways but if i end up needed a long shaft later on for a new boat, i dont want to have to make this change again.


----------



## cajuncook1 (Jul 12, 2011)

There are transom jacks that can serve your purpose, without having to mess with converting to a short shaft. Pappy, would be a good resource to get some solid information regarding this matter.

Just make sure your anti-cavitation plate on your lower unit is about equal to or +/- an inch from the bottom of your boat/transom. You will get better performance that way.


----------



## crazymanme2 (Jul 12, 2011)

All you need to make it a short shaft is a short drive shaft.The shift rod & water tube can be cut.

Short drive shafts by me run about $75.


----------



## Busbey (Jul 14, 2011)

which would be a better solution to my issue? how much is the plate? general balpark

when cutting the shift rob and water line, is this something a novice could do with general garage tools?


----------



## crazymanme2 (Jul 14, 2011)

> when cutting the shift rob and water line, is this something a novice could do with general garage tools?



yes

hacksaw,tubing cutter & a good eye. =D>


----------



## cajuncook1 (Jul 14, 2011)

Busbey said:


> which would be a better solution to my issue? how much is the plate? general balpark
> 
> when cutting the shift rob and water line, is this something a novice could do with general garage tools?



These are some considerations for jack plates. You maybe able to get a local machine shop or tech shop to fabricate one.(A Tech teaching shop may be able to make you a simple jack plate for a little more than the cost of the metal or supplies). My brother did that for his boat and motor. This way if you want to use it on other boat that requires a longer shaft you are good either way. 

But if you wish to make it short shaft. Please be sure you have the correct measurements, of the water tube and the shaft rod. The water tube will have to be cut a certain angle at the very end. Also you will have to get a short drive shaft for the motor.


https://www.iboats.com/Outboard-Jack-Plates-Mounting-Brackets/dm/cart_id.421601306--session_id.442370411--view_id.217144

https://www.iboats.com/Adjustable-Outboard-Motor-Mounts/dm/cart_id.421601306--session_id.442370411--view_id.217143


Good luck


----------



## Busbey (Jul 14, 2011)

Thanks for the info. Still waiting on my buddy to take the carb apart and let me know what he thinks. Once I get it back home, I will start thinking about cutting or adding.. Still need to get this thing running first.


----------



## Busbey (Jul 25, 2011)

still waiting on my buddy to work on the motor. he was on vacation for a week. 

as for the long shaft / short shaft issue, i found this.. https://www.basspro.com/webapp/wcs/stores/servlet/Product_10151_-1_10001_8782_225011002_225000000_225011000?cm_ven=bazaarvoice&cm_cat=RLP&cm_pla=8782&cm_ite=productname_link

i am still "if" about just ordering the drive shaft and cutting as suggested. if there is a tutorial or pics showing someone doing this, it would help my decision making. since i do not know how everything looks inside, i just cant make up my mind. 

would someone happen to have some pics of this process?


----------



## jasper60103 (Jul 25, 2011)

Busbey said:


> still waiting on my buddy to work on the motor. he was on vacation for a week.
> 
> as for the long shaft / short shaft issue, i found this.. https://www.basspro.com/webapp/wcs/stores/servlet/Product_10151_-1_10001_8782_225011002_225000000_225011000?cm_ven=bazaarvoice&cm_cat=RLP&cm_pla=8782&cm_ite=productname_link
> 
> ...




I would go for the jack plate. Several members here have used them with success.


----------



## Busbey (Jul 25, 2011)

good enough for me. thanks!


----------



## jasper60103 (Jul 26, 2011)

Busbey said:


> good enough for me. thanks!



Be sure to checkout baitcaster's mod...

https://www.tinboats.net/forum/viewtopic.php?f=21&t=14160&start=75


----------



## Busbey (Jul 26, 2011)

I found a much cheaper alternative. i think i may give it a go.... thoughts?

"""" The aluminum is 3/8" angle stock, the plywood is 2-3/4' pieces screwed/glued together. I need to drill the last 4 holes to attach the unit to the old transom. It seem sturdy enough to hold my 25Merc. ALL metal parts are either aluminum or stainless. """""""

https://forums.iboats.com/showthread.php?t=229049&page=1


----------



## nomowork (Jul 26, 2011)

Busbey said:


> New gas mixed 50/50.



Is this a 2 stroke?


----------



## jasper60103 (Jul 27, 2011)

Busbey said:


> I found a much cheaper alternative. i think i may give it a go.... thoughts?
> 
> ...



Yep, you can certainly make your own jackplate.


----------



## Busbey (Jul 27, 2011)

I mean 50:1 but yea 2 stroke


----------



## Busbey (Jul 29, 2011)

so i am getting a little agitated with my buddy not even taking the carb off yet. i know he is doing me a favor but come on already. geez. 

anyways, i am heading out of town this weekend for a surprise b day get away. when i get back, i am tackling the boat full force, getting gluvit for inside and painting outside and upper inside half. from there, building a deck for it. once i see how he is doing from my mid point of completion, i might just bite the bullet and do it myself or learn or just pay someone. i will need the motor to build the jackplate. 

really hope he can figure it out soon. i know he is a busy guy but i am sure if i had it here in my garage, you guys could help me through small issues.


----------



## Busbey (Aug 4, 2011)

i think i am just going to add a nice home made jack-plate for obvious reasons when considering price and effort. 

spoke to my friend and he was going to take apart the carb and clean it a bit, check things out. from there i do not know what else he is going to do. 

if i was going to just have him clean everything and put new seals and such "if needed", think i can get it back to my house and you guys could help me dial it in? i hate having it at his house and being a burden in his garage


----------



## DM613 (Aug 4, 2011)

Foam is not clear up without dismantling and cleaning properly. You can start your first adjustment of the needle at low speed to 1.5 turns and twist it slowly until the engine accelerates and finally spits then leans back to 1 / 4 turn and leave. Thats a good fit approximation.


----------



## Busbey (Jun 4, 2012)

a few questions guys. i got it all together and running yesterday. just need to iron out a few minor issues. 

what is this plate? obviously homemade and leaks a tad from the very bottom. but where it leaks from, it drips on the spark plug wires. what initially went here and is it worth it to buy whatever it is? 






next up is the pulley part. where the bolt is, i have since added a washer. problem is, when i tighten it "tight" i cant pull the cord. when it is loose enough to pull, the tries to come off and hit and sparks fly, etc etc. so we need to get the proper fix for this. 





main issue here.. fuel. i have an old 6hp Montgomery ward that is amazing. no issues, starts on first pull every time, etc etc. great little motor. so, i have a gas tank that i use with that, only 2gallons. has the manual bulb primer which works. everything is good on that setup. BUT, when i use that can and hose and pump on this motor, it stops running. you have to keep pumping the primer to keep the motor going. so, i have a 2psi fuel pump lying around and attached it to the motor, bypassing the primer. will run all day it seems. normal. is there a problem with the motor or what? at this point, i need the above issues fixed and a jack plate made and i am ready to take it out. not sure if i should just hook up this fuel pump and say screw it or what. 

on a side note, i left the motor off, fuel pump on, nothing leaked. so i am assuming this has a built in shut off or something where it is not pumping anymore once enough fuel is needed? is 2psi a good number? i don't want to waste a bunch of gas and possibly ruin something from pumping to much fuel in. 

lastly, 50:1 mixture? says 100:1 on the motor and smokes pretty good with 50:1 in the garbage can i had it in yesterday. 

guys, thanks. i hope to get some good answers and out on the water soon!


----------



## JMichael (Jun 5, 2012)

My guess on the metal plate appears to be a home made thermostat cover. The slop in your recoil starter most likely means you'll need to replace the worn parts. It sounds like you need to rebuild the fuel pump on your motor. You can get kits for this just like buying a carb kit. It's not unusual for a motor to seem to smoke a lot when run in a barrel. While it might run OK on 100:1, I'd continue to run it on 50:1. Worst case is it smokes just a little bit more but at least you won't harm your engine from lack of lubrication. And once you get it out on the lake, I bet you won't even notice the smoke.


----------



## GYPSY400 (Jun 5, 2012)

I think J/E backpedaled on the 100:1 mix and went back to 50:1 after only a couple of years. It should run fine on 50:1.. If you choose to run 100:1, I would run a synthetic.


----------



## Pappy (Jun 5, 2012)

The issue with 100:1 was an issue that manifested itself during off-season storage and internal corrosion. From those issues OMC came out with a service memo that stated that engines with the 100:1 rating were to be run on 50:1. This is something I have seen firsthand in brands other than Johnson/Evinrude as well. We have a 3 cylinder Yamaha apart on the bench now that has been run on 100:1 and the crank counterweights are lightly rusted. This is going to happen if you run light oil ratios. The heavier ratios will leave a better and heavier protective film of oil on internal parts once the gasoline evaporates, no ifs ands or buts about it.
That rear plate is home made and needs to be replaced with the proper thermostat cover with a new gasket and thermostat installed as well.


----------



## Busbey (Jun 6, 2012)

thanks for the info guys. 

as for the pulley part, i have replaced the coil spring and the gear piece. the bolt attaches to a metal piece down below the coil spring. i am thinking of just getting some lok tight and calling it a day but then that random even when it falls off i will be the farthest from the ramp. just my luck.


----------



## Busbey (Jun 12, 2012)

could someone point me in the right direction to an exploded view of this thermostat area? i cant seem to find anything and want to compare the view to what i have and which parts i think i should get. 

much appreciated!


----------



## JMichael (Jun 12, 2012)

Here's an exploded view for an 87. The diagram and text don't match up for the 88 model on this site so I linked the 87 which I think is the same. 
https://www.crowleymarine.com/johnson-evinrude/parts/45764.cfm


----------



## Pappy (Jun 12, 2012)

Do you have a dealer near you?? If so, by all means give him the chance to look up the parts for you and sell them to you!!


----------



## Busbey (Jun 13, 2012)

i guess this is what i need then?

https://www.marineengine.com/newparts/part_details.php?pnum=OMC0433379&ptype=&Engine=&Model=

i will look for a dealer and bring it in. thanks for the advice.


----------



## JMichael (Jun 13, 2012)

You're probably going to need an original cover in order to be able to install a thermostat in it.


----------

