1986 Johnson 30 water pump

[oldboat1]

Did the powerhead overheat (too hot to touch on top of the head)? The water tube may not be seated in the water pump grommet. If not overheating, run a piece of weedwhacker line up into the tell tale -- far as it will go. Maybe just blocked.

 

[jasper60103]

Got everything together finally. Took it for a test drive and no water comes from the tell tale. It does blow air though. What could be going on? I'm hoping I installed it right since it is pushing air out?

Are you running on a hose or a barrel? If in a barrel make sure you have it deep enough in the water. Here’s my old Johnson 30 hp.

 

[flyingscott]

Did you put the key in the impeller? Water tube lined up correctly?

 

[racerone]

If there is no water in the block then exhaust finds a way out of the tell tale.---Did water tube come out with the pump ?-----If so was it installed in the exhaust housing first ?

 

[MN30hp]

I was running it in the lake so water availability shouldn't be an issue. The water tube did come out with it. I installed it in the exhaust housing first then lined it up with the impeller during the reinstallation. Key installed. I blew compressed air back threw the tell tale when the lower unit was off.

 

[MN30hp]

Took everything apart and reinstalled. Unfortunately I didn't take a picture of how the key/water pump was installed. This is how I installed it, flat side against the drive shaft, fat lobed end into the pocket of the water pump. I turned the drive shaft and could feel it turning the impeller. Reinstalled everything and still no water. What gives? What basic thing am I overlooking? Verified again before snugging up the lower unit that the water tube was installed correctly, blew air through it and the passage is clear. Help!

 

[racerone]

Stainless plate under the impeller installed correctly ?

 

[MN30hp]

Stainless plate under the impeller installed correctly ?

Yes. Double checked and only 1 way it can go on so the bolt holes line up.

 

[tphoyt]

Is that 100% the correct impeller?
The fins look a bit short to me but it could just be the photo. Do you have the old impeller? Is it the same?

 

[oldboat1]

Is the powerhead getting hot when running? Too hot to touch?
Are the intakes in the lower unit clogged?
With the lower unit assembled but not yet connected to the leg, you can test pump operation using a container of water deep enough to cover pump. You can use a drill, but turning by hand (clockwise) can work. If the water bubbles up out of the tube grommet, assume the pump works.

Operation of the tell tale is not critical, but can indicate that water is not getting up to the powerhead. If the motor is not overheating (too hot to touch, over 160F if measured), water is getting up to the powerhead and through it.

Did you test for engine temp, and use a prod about 6 inches or so into the tell tale? I don't find compressed air the most efficient test for the cooling system. (BTW, with the l.u. removed, you can also push water up and through the powerhead through the water tube. Use a hose and step down the diameter to test.) Water should gush out below the p.head.

 

[MN30hp]

Is that 100% the correct impeller?
The fins look a bit short to me but it could just be the photo. Do you have the old impeller? Is it the same?

Compared it to the old one and they're the same. Just the key type is different.

 

[MN30hp]

Is the powerhead getting hot when running? Too hot to touch?
Are the intakes in the lower unit clogged?
With the lower unit assembled but not yet connected to the leg, you can test pump operation using a container of water deep enough to cover pump. You can use a drill, but turning by hand (clockwise) can work. If the water bubbles up out of the tube grommet, assume the pump works.

Operation of the tell tale is not critical, but can indicate that water is not getting up to the powerhead. If the motor is not overheating (too hot to touch, over 160F if measured), water is getting up to the powerhead and through it.

Did you test for engine temp, and use a prod about 6 inches or so into the tell tale? I don't find compressed air the most efficient test for the cooling system. (BTW, with the l.u. removed, you can also push water up and through the powerhead through the water tube. Use a hose and step down the diameter to test.) Water should gush out below the p.head.

I have not tested the temp of the motor while running yet. I used compressed air from the tell tale and verified it coming out of the water tube with my hand. So when testing it without the lower unit attached where does the drill attach to, drive shaft?

 

[racerone]

Very hard to assemble one of those pumps so that it DOES NOT work.-----What condition is the grommet in at the top of the water tube ?

 

[MN30hp]

Very hard to assemble one of those pumps so that it DOES NOT work.-----What condition is the grommet in at the top of the water tube ?

Hmm that I'm not sure. The nylon washer that goes on top of the water tube was kind of warped, did my best to straighten it out and reused it.

 

[MN30hp]

Good news! Everything is working as it should. The last time I tested it was in a bucket of water but the water line was only just above the intakes. I failed to realize that without the muffs forcing water up to the pump level that water was not reaching the pump. Der. It is shooting water out like a missile now. Thanks all for the help

 

[MN30hp]

One problem fixed, another problem realized. It appears the head gasket is leaking on the port side. You can see a water droplet in the pic. It is leaking a drop every few seconds. Still seems to run and idle well. Honestly I'm not sure if this is a new development or not. I can't recall if I've ran the boat in the yard before with the cover off and looked around at it. Tested compression at 125 top and 115 bottom. What do I need to know about this? Can it be used for awhile as is?

 

[jasper60103]

One problem fixed, another problem realized. It appears the head gasket is leaking on the port side. You can see a water droplet in the pic. It is leaking a drop every few seconds. Still seems to run and idle well. Honestly I'm not sure if this is a new development or not. I can't recall if I've ran the boat in the yard before with the cover off and looked around at it. Tested compression at 125 top and 115 bottom. What do I need to know about this? Can it be used for awhile as is?View attachment 351923

 

[jasper60103]

It wouldn’t hurt to check the torque on those bolts.

 

[tphoyt]

Can it be used for awhile.
Thats a million question.
You could try to re torque the bolts but in my experience even if stop the leak it will likely start again after a few heat cycles. Your best bet would be to replace the head gasket sooner than later. Don’t forget to lap the head.

 

[MN30hp]

Can it be used for awhile.
Thats a million question.
You could try to re torque the bolts but in my experience even if stop the leak it will likely start again after a few heat cycles. Your best bet would be to replace the head gasket sooner than later. Don’t forget to lap the head.

That's what I assumed to. I have used it a couple times since with no change in performance. What is lapping the head? Something a machine shop does?