1989 Johnson 25 HP. Multiple Issues

[Jlockler]

Picked this motor up for close to nothing knowing it needed some work. First round of maintenance as follows.

water pump/impeller
Thermostat
carb pulled and cleaned
Fuel lines flushed

Motor ran okay aside from it taking a while to get it started but once warm it was fine. Fourth time out motor quit on me and havent been able to get it started since. Second round of maintenance as follows.

Spark plugs
Ignition coils continuity check good
carb pulled and cleaned
new primer bulb and hose
new tank

Able to get it started sometimes on muffs but it only stays running for a few seconds before bogging down. Spark is good on plugs. Compression 90/90. Starting to think primer solenoid or fuel pump. I dont have any experience with testing these two components so any help troubleshooting would be appreciated.

Another issue that started after the motor died on me is the starter only engages for 1 to 2 seconds even with the key still turned. I pulled and inspected starter. Also cleaned all the electrical connections. Still having the same issue, however I noticed when doing a compression test that when the spark plugs were pulled the starter would stay engaged the entire time the key was turned, but when plugs are installed its only 1 to 2 seconds. Prior to the engine dying on me the starter would stay engaged as normal this has only been an issue recently.

I know this is alot, but I've been trying to solve this without having to reach out. I have a minor mechanical background and I'm open to any help provided. Thank you in advance.

 

[ct1762@gmail.com]

i'd pull the head and exhaust cover to see what the cylinders/pistons look like, but first do some tests on the stator and sensor coil to be sure they are putting out good voltage and aren't going to ground. Do you have a DVA adaptor for your multimeter and the factory service manual? the throttle plates need to just barely start to move when the cam roller hits that mark on the throttle cam. Are you sure the throttle plate in the carb is 100% closed when trying to start it? Slow speed needle adjusted properly? sparks a 11mm gap on air gap tester? if it's the fuel pump, it will start up and idle, but run out of gas unless you squeeze the bulb so don't think it's that. make sure the float drop setting is atleast 1 1/8th inch with the carb right side up. if it's too low, it will not let fuel in at mid and high speed. easy way to tell is pull the bowl drain screw and hopefully gas pours out.

 

[Jlockler]

i'd pull the head and exhaust cover to see what the cylinders/pistons look like, but first do some tests on the stator and sensor coil to be sure they are putting out good voltage and aren't going to ground. Do you have a DVA adaptor for your multimeter and the factory service manual? the throttle plates need to just barely start to move when the cam roller hits that mark on the throttle cam. Are you sure the throttle plate in the carb is 100% closed when trying to start it? Slow speed needle adjusted properly? sparks a 11mm gap on air gap tester? if it's the fuel pump, it will start up and idle, but run out of gas unless you squeeze the bulb so don't think it's that. make sure the float drop setting is atleast 1 1/8th inch with the carb right side up. if it's too low, it will not let fuel in at mid and high speed. easy way to tell is pull the bowl drain screw and hopefully gas pours out.

I do not have a DVA adapter but should be able to borrow one from work, i will have to get a flywheel puller to get to the stator and sensor coil. I have a digital SELOC manual but not the factory manual. Would i need to use the adapter to check voltage? shouldnt i be able to check voltage with the multimeter leads? Stator and coils are new to me please excuse the lack of expierence.

Throttle plate is definitly 100% closed when trying to start, the slow speed needle was adjusted prior to this issue, after being seated its probably about 4 to 5 full turns backed out. I tried adjusting while engine was idling but it never seemed to make any difference. This was done when motor still ran.

I pulled plugs one at a time and grounded to engine block while visually verifying spark, i did not use an air gap tester but will look into that. However plugs are brand new.

When i pulled the carb to clean the float drop was about 1 3/16". Would a 1/4" make that much of a difference? I havent pulled the drain plug after trying to start yet. That was on the list last night but it got to late. I will check that later this evening after work.

I was told by a buddy to pull the small fuel line from the primer solenoid to the top of the carb, pump up the bulb and turn key to run position but do not start, push key in and see if fuel comes from hose. If not solenoid needs to be replaced.

 

[ct1762@gmail.com]

the float drop is low, yes. does the bowl look dry? Honestly i've done so many of these carbs and realized it's better to set the float slightly up from level on the free end opposite the needle and seat, and the drop 1 1/4-1/2 inches (safer to make it 40mm). you can blow through the fuel nipple to make sure it's open. doesn't matter if the float hits the bottom of the bowl... never had an issue. is the cam roller on the carb in good shape?
the fuel primer solenoid does not usually need replacing unless it's cracked ... and even then for superficial cracks i put rtv sealer in it for good measure. new ones are pricey! if it's leaking when the valve is opened, ebay has rebuild kits for $12. how wet or dry are the plugs when it won't start?