Johnson 30hp Help

[DriftinMT09]

Took the boat out yesterday, and the motor seemed to be running okay. It has always bogged down when in gear, and stalled at low rpm. It kept coughing and stalling when just idling in neutral. We ran it around around the lake at roughly 50-70% throttle with no issue. Stopped to check out if I can find the source of my water seapage into the back hull area, and when I restarted it, it would not rev out. It felt like it was hitting a limiter, or maybe only hitting on one cylinder. Just off idle, it ran fine, and smoothly. Luckily the lake wasn't too rough, and we were able to put put back to the launch.

 

[DriftinMT09]

So far, I repaired what I think was the kill switch wire that had been pinched prior in the hood tabs (wire was corroded).

I also noticed a bolt had walked out of the top cover (cylinder head cap?). It threaded back in, and I just snugged it down. Noticed some whitish corrosion on the opposing side, like maybe water was getting out?

 

[DriftinMT09]

I had also noticed it that it didn't initially start pumping out water from exit nozzle, until it had been running for maybe 45 seconds. It seemed like a normal amount of water and a decent amount of flow coming out of the nozzle once it started.

Kinda thinking the guy who sold me the whole package deal was really lying, when he said they never had one issue in the 2 years they owned it.

 

[jasper60103]

I would add a new water pump kit as preventive maintenance and peace of mind. You never know when it was last changed.

Sent from my SAMSUNG-SM-G900A using Tapatalk

 

[DriftinMT09]

I would add a new water pump kit as preventive maintenance and peace of mind. You never know when it was last changed.

Sent from my SAMSUNG-SM-G900A using Tapatalk

Downloaded the service manual that is linked in the "manuals" section. Can't really tell if you can unbolt the gearcase without pulling the prop. Ordered a new water pump kit, with a new head cap gasket, so I can also replace the thermostat and gasket.

After reading through a few other threads, I think maybe it was in limp home mode, as maybe it was overheating.

 

[Pappy]

You should have heard a hot horn as well. If the engine is a later model with the S.L.O.W. system in it the horn should beep or chirp one time when the key is cycled to the on position. That indicated the system self checked and that your hot horn is working. If not....add that to the to-do list but first things first.
You have not let us know what year the engine is. Let's start there.

 

[DriftinMT09]

You should have heard a hot horn as well. If the engine is a later model with the S.L.O.W. system in it the horn should beep or chirp one time when the key is cycled to the on position. That indicated the system self checked and that your hot horn is working. If not....add that to the to-do list but first things first.
You have not let us know what year the engine is. Let's start there.

My apologies, it's a 1990 Johnson 30hp J30TELESS. I have never heard a hot horn or any short of chime on it at all. There is no key, as it is a tiller, and it doesn't make any sort of chime when placing the kill tether key on the switch.

 

[RaisedByWolves]

Look down #-o

 

[RaisedByWolves]

Yeah, that won’t have a horn.

It does sound like you were going into limp mode with a hot motor though.

Change out that impeller.

The sneezing and stalling are the motor telling you it is too lean. Either adjust the low speed mixture or rebuild the carb.

And no, there’s no need to remove the prop.

 

[DriftinMT09]

Yeah, that won’t have a horn.

It does sound like you were going into limp mode with a hot motor though.

Change out that impeller.

The sneezing and stalling are the motor telling you it is too lean. Either adjust the low speed mixture or rebuild the carb.

And no, there’s no need to remove the prop.

Thank you! Is there gaskets in between the lower gearcase and the upper portion where the impeller is? I ordered a kit with the whole housing, and it shows maybe 1 or 2 seals, but they appear to be for the impeller case. The manual only lists putting sealant on the 4 bolts, and not the mating surfaces. Sorry for the new guy questions, my first rodeo into outboards (aside from doing an exhaust manifold gasket on my parents Merc on the back of their pontoon in the lake).

 

[Pappy]

You are wise to order the complete kit.
The gaskets are usually for the lower wear plate and no sealer is required for them. Sealer is normally used on the bolts to insure they will come out again the next time you service the pump. A good waterproof grease will also work if liberally applied or a liquid teflon sealant is even better on the bolts.
If the pump comes out in pieces make sure there are no pieces in the water tube that goes to the powerhead.
There will not be a hot horn on a tiller model by the way. Thanks for adding the model year information.
When you go to check your work make sure the water level in the barrel (if used) is over the lower mounts on the side of the exhaust housing. This will insure the pump is submerged. They are not self priming pumps.

 

[DriftinMT09]

You are wise to order the complete kit.
The gaskets are usually for the lower wear plate and no sealer is required for them. Sealer is normally used on the bolts to insure they will come out again the next time you service the pump. A good waterproof grease will also work if liberally applied or a liquid teflon sealant is even better on the bolts.
If the pump comes out in pieces make sure there are no pieces in the water tube that goes to the powerhead.
There will not be a hot horn on a tiller model by the way. Thanks for adding the model year information.
When you go to check your work make sure the water level in the barrel (if used) is over the lower mounts on the side of the exhaust housing. This will insure the pump is submerged. They are not self priming pumps.

By lower mounts, do you mean the two intake grates that are in the lower gear housing? If I'm understanding the manual correctly, it looks as if the impeller and housing are right above the split in the lower unit housing, just above the gear case half. So I basically need water up to that point where the impeller housing is, in order for it to pick up water correctly?

I'm also doing the thermostat and gasket at the same time. Not sure how well this engine was taken care of prior. I have noticed a lot of oil/oily debris in the lower cover of the motor. Not sure if my fuel lines have deteriorated over time and are wicking out, or if it just dumps out the face of the carburetor when the engine is tilted into the up position.

 

[LDUBS]

By lower mounts, do you mean the two intake grates that are in the lower gear housing? If I'm understanding the manual correctly, it looks as if the impeller and housing are right above the split in the lower unit housing, just above the gear case half. So I basically need water up to that point where the impeller housing is, in order for it to pick up water correctly?

The water level should be above your impeller. Basically submerge the impeller. As Pappy says, the water pump will not draft/self prime. So you want it to be full of water when you start the motor.

 

[RaisedByWolves]

This is a video I took of my motor when I was trying to get help diagnose what was going on. This was a bad temp sensor.


https://www.youtube.com/watch?v=UwMU9Q5_XP0

And another where its running good, then goes into limp mode @:50


https://www.youtube.com/watch?v=cAeJAnX-D4M

 

[DriftinMT09]

This is a video I took of my motor when I was trying to get help diagnose what was going on. This was a bad temp sensor.


https://www.youtube.com/watch?v=UwMU9Q5_XP0

And another where its running good, then goes into limp mode @:50


https://www.youtube.com/watch?v=cAeJAnX-D4M

Mine made the identical "rev limiter bounce" that yours made in the first linked video. I'm hoping it is not the temp sensor, and that maybe my thermostat stuck closed, or the impeller has improper output (damaged fins).

 

[RaisedByWolves]

You can rule in/out the temp sensor by disconnecting it.

Do that as a test only, definitely test the T stat and replace the impeller regardless.

 

[DriftinMT09]

You can rule in/out the temp sensor by disconnecting it.

Do that as a test only, definitely test the T stat and replace the impeller regardless.

It will run without the temp sensor plugged in?

 

[user 21074]

Took the boat out yesterday, and the motor seemed to be running okay. It has always bogged down when in gear, and stalled at low rpm. It kept coughing and stalling when just idling in neutral. We ran it around around the lake at roughly 50-70% throttle with no issue. Stopped to check out if I can find the source of my water seapage into the back hull area, and when I restarted it, it would not rev out. It felt like it was hitting a limiter, or maybe only hitting on one cylinder. Just off idle, it ran fine, and smoothly. Luckily the lake wasn't too rough, and we were able to put put back to the launch.

You sure your not getting water in one of the cylinders?Loose head bolt and idol and stalling issues.Pull the head and inspect gasket.Did you verify even if this motor has a rev limiter built in the power pac?

 

[DriftinMT09]

Took the boat out yesterday, and the motor seemed to be running okay. It has always bogged down when in gear, and stalled at low rpm. It kept coughing and stalling when just idling in neutral. We ran it around around the lake at roughly 50-70% throttle with no issue. Stopped to check out if I can find the source of my water seapage into the back hull area, and when I restarted it, it would not rev out. It felt like it was hitting a limiter, or maybe only hitting on one cylinder. Just off idle, it ran fine, and smoothly. Luckily the lake wasn't too rough, and we were able to put put back to the launch.

You sure your not getting water in one of the cylinders?Loose head bolt and idol and stalling issues.Pull the head and inspect gasket.Did you verify even if this motor has a rev limiter built in the power pac?

From my limited understanding of outboard boat motors, it wasn't the actual head bolt, out was one of the head cap bolts. I had both of the spark plugs out, and both were pretty carboned up. Neither of them were cleaned off, like the engine was ingesting water. I'm not sure if the engine has a rev limiter, but my saying "rev limiter" is based off a bouncing rpm, that kept hitting a peak in the same place. I'm hoping it's not a head gasket, but my experience with other 2-stroke engines, if the head gasket goes, the plugs and piston tops are usually very grayish color, and the engine doesn't live to long after if not immediately fixed.

 

[CedarRiverScooter]

I it has oil all over the power head, it could be exhaust gasket or top crankshaft seal leaking.