15hp johnson problems starting after winter

[Superduck1]

Last year I started having problems with with it starting. So we went through all the issues. Ended up rebuilding and cleaning the carb, new plugs, rebuilt the fuel pump. Eventually replaced the ignition coil. Took it out no problems starting, but the shift linkage disconnected so it was starting in gear. So after out once I took it off the boat and laid it in the shed. Put it on the boat and now having starting problems. I replaced the gas and got it to started with a little starting fluid. I know bad. So before I drive myself crazy again any ideas?

 

[oldboat1]

I would start here: https://www.ebay.com/itm/193686065796?hash=item2d1896d284:g:AcMAAOSwNXZfcQQX Start with water pump replacement, and read the instructions thoroughly. Complete the work. Then move to the magneto/ignition, and do the same. Review your two threads in light of the details involved for each procedure, and go back to work on the motor.

 

[Superduck1]

Theres no issue with the water pump. I replaced the impeller last year and have no issues with it spitting water when running.

 

[oldboat1]

Then you can presumably check that off the list. Point is to do/redo each system with a manual in front of you.

 

[flyingscott]

what yr is your motor? model #?

 

[oldboat1]

('93 J15RET unless he moved on to another one.)

 

[Superduck1]

Its the same one. It was laying on the ground all winter if that makes a difference. Also I forgot to run it dry.

 

[flyingscott]

Make sure the carb is clean. Is the cam roller in good shape?

 

[Superduck1]

The carb should be clean. I rebuilt it last year, unless sitting all winter caused it to foul up. The cam roller looks to be in good shape.

 

[Crosbyman]

here is the answer . Also I forgot to run it dry.

my two option are....

run it dry​

store it full of fuel and gas preservative​

​

if you have good sparks and compression I think you only have one option....clean the carb​

 

[Superduck1]

Well I think all my tinkering is moot. Checked compression this morning, top plug was at 60ish and the bottom 65.

 

[flyingscott]

Did you keep pulling until the needle stopped? Minimum 5 pulls

 

[JDusza]

Be wary of the compression numbers. The gauge could be bad. What are the chances 2 cylinders are gone at the same time?
More likely the gauge itself is off. In addition to magnitude, the other thing you want to see from a compression test is the consistency between cylinders. You have that. 10% variation across the cylinders is a common guideline.
Most likely you have a fuel flow problem from the way the unit was stored. Wasn't run dry, stored flat. One season's storage can give you a problem. In all likelihood, your carburetor is gunked up.
J

 

[Sea Rider]

Once the carb is pristine clean, buy a motor stand or build one for yourself, motors should be kept resting full vertical. A stand will also serve well for running carb dry, flushing, preventive maintenance and general repair purposes...

Happy Boating​

 

[oldboat1]

And...stands are fun to make. Make it big enough to accommodate a big plastic trash can so you can test and tune at bit at home.

 

[Superduck1]

Well the compression tester is brand new from advanced auto parts. I tested it again, and got 80 on the top and 65 on the bottom this time making sure to do minimum of 5 pulls on each. I'll take the carb off and give it a good cleaning. When it does run, it will die real fast at a low idle or speed.

 

[Sea Rider]

If after cleaning the carb to an immaculate state the motor keeps dying at idle or speed seems it's an electrical related issues. Just in case, remove the Ignition Coil's ground cable that bolts to the lower crankcase, bend it back and forth, if found too easy to bend with minimum restriction chop the end terminal, peel new wire and install a new terminal...

Happy Boating​

 

[Crosbyman]

see diagram

 

[Superduck1]

It doesnt die at speed. It ran great at high rpm, when in low rpm it would sputter out. I took the carb off amd took it all apart sprayed all the ports etc and after putting it back on no luck. I had my compression numbers wrong, top is 80 bottom is 70. I think I'm to the point of just taling it off the boat and doing a full rebuild.

 

[oldboat1]

see diagram

A stand helps keep the carb from sucking in exhaust gases. A box fan doesn't hurt either while testing engine.