'78 Johnson 25 frustrations

[Oldgenetics64]

So I changed the impeller, gaskets etc. Then had to change the leaking fuel pump to get it to start. Pumped and primed, it started almost immediately. After about 15 seconds of running nicely, no telltale. I could swear that I've got everything lined up and seated correctly.
Am I being paranoid about how long it's taking the telltale to start or do I need to tear it down again?

 

[flatheadsteve]

Give it 60 seconds it's not going to overheat in that short amount of time. Not sure on specifics of that model but some outboards take a bit before they start flowing.

 

[Oldgenetics64]

Thanks, before replacing the water pump, it would start flowing in 15-20 seconds. I've never worked on an outboard motor before so I thought I should double check.

 

[Crazyboat]

Any chance the outlet hole is clogged?

 

[Oldgenetics64]

I'll double check. But I doubt it. All the work has been done while the motor was still on the transom, sitting in the driveway.

 

[MrGiggles]

I'd say it should be going within ten seconds. I had an 83 25hp Johnson and it would start almost immediately.

Check the easy stuff first. Are you running it on muffs or in a barrel? If it's in a barrel, the water level needs to be above where the water is positioned in the lower unit, usually 2-3 inches above the cavitation plate.

Also make sure the telltale nozzle and hose are clear. Mud daubers will make a home in them. If it was stopped up and the water pump is working, you should still have water exiting the exhaust ports on the midsection.

 

[mirrocraft16]

I have the same motor here, it pumps water almost right away. I just had it out and started it after a long sit.
When I first bought mine, it had sat for a number of years and both the telltale tube and the thermostat were clogged up pretty bad. The last owner used it in shallow water and the block was also full of sand. It took me an hour to get it all flushed out clean. Its been fine though for the past 25 or so years since.

Did you put the impeller key back in?
Is the thermostat new or at least clean?
Test run the motor in a tub of water, not on ears, those early motors just don't seem to pump well any other way. I have an old extra deep recycle bin from our old trash service that works great, it holds about 40 gallons or so. It likely uses less water in the end vs running the hose full time.

Pull the tube off the telltale and make sure its clear all the way up to the block. I've had things crawl up that hose pretty far and block flow on motors in the past. I've got into the habit of putting a piece of tape over the telltale hole when I park the boat to keep critters out.

 

[LaqueRatt]

I got one too, but it's a 'rude. Had it running yesterday. I agree it should be peeing almost immediately. Wish my Merc was like that.

 

[Oldgenetics64]

I checked and the telltale is clear. Looks like I'll be tearing it down again to find the issue. 30 seconds in the "tank" and nothing. Premix settled so it's smoking heavier than usual.

 

[airshot]

From your video, it looks like your motor needs to be deeper in the water. Upon initial start 2-3 inches of water over that plate/ fin is recomended !! When you took out the old impellor was any of it missing...broken off ears etc?

 

[Oldgenetics64]

No broken ears, just a seriously worn out and overheated impeller. I'll take pics of it tomorrow morning. I can try deeper water but I doubt that will change much.

 

[flatheadsteve]

I agree doesn't look deep enough In the water in that video.

 

[ripdmup]

x3 on the water depth

Off topic but do you remember Haps bar over in Timber?

 

[LaqueRatt]

Yep, not enough water. When on the boat I put spare tires and pieces of firewood underneath the barrel. Or just get a deeper barrel.

 

[Pappy]

Finally..........Airshot pretty much nailed it.
Wondered how long it would take for someone to come up with checking the simple things first.
The water pump is not a self priming pump. Never has been and never will be. You have to submerge the pump in water when running in a barrel to get it to prime and pump. Not 2-3 inches above the cav plate as was mentioned. Nor do you need functioning thermostat to see the indicator start to produce water. Sure wish folks would quit answering questions when they are not sure what they are talking about. Good job Airshot!

 

[MrGiggles]

iones inWondered how long it would take for someone to come up with checking the simple things first.
The water pump is not a self priming pump. Never has been and never will be. You have to submerge the pump in water when running in a barrel to get it to prime and pump. Not 2-3 inches above the cav plate as was mentioned. Nor do you need functioning thermostat to see the indicator start to produce water. Sure wish folks would quit answering questions when they are not sure what they are talking about. Good job Airshot!

2-3 inches above the cav plate is more than enough to submerge the pump on most motors. I did outline that the water level needs to be higher than where the pump is positioned in the lower unit.

Maybe you should read everything before waltzing in and assuming everyone else is wrong like you so often do. You possess a wealth of knowledge, but the pompous attitude is a little off-putting to members that are contributing, wrong or not.

 

[Pappy]

And maybe you should do some measuring and let me know that the pump is down that low on "most motors". Go ahead and check any 18-25hp engine such as this one first. Please do not get butt hurt about this. We are only looking for folks to get in the habit of writing good, accurate and repeatable information and to get in the habit of checking the simple things first. Was not personal that's why you were not mentioned by name.
Since not all lower units are the same the safe answer in all cases is to "submerge the pump". That information is accurate and repeatable and simple. sorry about the hurt feelings.

 

[MDCrappie]

And maybe you should do some measuring and let me know that the pump is down that low on "most motors". Go ahead and check any 18-25hp engine such as this one first. Please do not get butt hurt about this. We are only looking for folks to get in the habit of writing good, accurate and repeatable information and to get in the habit of checking the simple things first. Was not personal that's why you were not mentioned by name.
Since not all lower units are the same the safe answer in all cases is to "submerge the pump". That information is accurate and repeatable and simple. sorry about the hurt feelings.

You say "Nothing personal" and made a point that Airshot got the call right first. When I read each of their replies they pretty much are identical, and MrGiggles was first.

From your video, it looks like your motor needs to be deeper in the water. Upon initial start 2-3 inches of water over that plate/ fin is recomended !! When you took out the old impellor was any of it missing...broken off ears etc?

I'd say it should be going within ten seconds. I had an 83 25hp Johnson and it would start almost immediately.

Check the easy stuff first. Are you running it on muffs or in a barrel? If it's in a barrel, the water level needs to be above where the water is positioned in the lower unit, usually 2-3 inches above the cavitation plate.

Also make sure the telltale nozzle and hose are clear. Mud daubers will make a home in them. If it was stopped up and the water pump is working, you should still have water exiting the exhaust ports on the midsection.

BTW - who is the "we" you are referring to? Are you a member of the staff, or are you assuming that all of the other members of the forum have the exact same objectives as you? Since "we" are not all the same wouldn't it be better for you to say "I" when expressing what you think. but not know to be 100% correct? Please don't get butt hurt, it's nothing personal. I'm just pointing out errors, like you sometimes like to do. See how it looks? Sorry if I hurt any feelings.

 

[LDUBS]

No broken ears, just a seriously worn out and overheated impeller. I'll take pics of it tomorrow morning. I can try deeper water but I doubt that will change much.

Put a new impeller in. I think (hope) you might be surprised if you raise the water level. Fingers crossed, let us know what happens.

 

[airshot]

Easy enough to try deeper, even go 6" deeper just to be sure !! If no good results then reconsider your pump replacement, or do it over.