I can't seem to get water through my outboard

[RickyD]

So I had 200 hours on a 2018 Honda BF40 outboard and decided to do the service with a friend's help. I was able to do this on my foredeck. Changed the oil, gear oil, spark plugs, and impeller. I put it in the water and the tell tail stream we very weak. If I idled for long the overheat alarm would go off. If I ran at at least 1200 rpm it would be fine but very little water coming out of the tell tail. So I figured that in the process we knocked some salt chunks inside the engine so I ran it in West Marine anti salt solution in a big container. No change. So I ordered and installed new thermostat. Before the installation I Poured CLR in, it poured out the bottom through the screens in the bottom end. Seemingly with no restrictions. Then poured the anti salt concentrate. No change. Then I pulled the bottom end off to be sure there was nothing evident there, turned the drive shaft as I thought maybe we lost the drive key, but I had the impeller turning. Put it back together, no water at all through the tell tail. It has to be salt right? Put it back in the bucket with lots of anti salt solution, no water engine hot. My final thought is that we are missing the connection between the tube at the bottom end and the tube above it. It seems as though the two units would not go together without those tubes lining up. It is hard to juggle them. Could it be that the first time we did it we pushed the upper part of the tube up and we did not get a good connection? Then we made no connection? Any suggestions besides call in the experts?

 

[SteveK]

I would doubke check the impeller to make sure it and not just the shaft is turning.

 

[rslifkin]

Have you tried back flushing the telltale hose? It's possible at this point that the telltale itself is clogged.

 

[twistedtree]

If the engine is overheating that I think it's more than just a blockage in the tell-tale hose. You replaced the impeller, so this would be a high probability fault area - I just don't have more to suggest since you have checked it - jut perhaps approach it as a certainty that it's the problem, and they there is something you overlooked, it's the wrong impeller, etc.


I'm also not familiar with the construction on that engine, but you mention a water tube connection between the upper and lower unit. Perhaps there is supposed to be some sort of seal or o-ring at that joint, and it got knocked out during the maintenance work? I'd check a parts diagram fro the lower unit to see what's supposed to be there. If that tube isn't a sealed joint then I could see the pump sucking air rather than water.

 

[Comodave]

Was the motor running ok before you did the impeller service? If it was then look at the work you did, you may have put the problem in during the service.

 

[DavidM]

I would doubke check the impeller to make sure it and not just the shaft is turning.

David

 

[Max Simmons]

I have the same outboard and last year I noticed weak flow. I used some thick weed wacker line and shoved it up through the pee hole, it dislodged some salt and started flowing nicely.

 

[DennisB1]

Assuming you installed the impeller correctly with the drive key you may have disconnected the water tube at that goes from the impeller thru the low housing to the engine block. If you drop the lower unit check the water tube for looseness if it is not sealed at both or one end you will have the problem you describe. I had it happen on a new Evenrude 25 Etec. It required removing the block to fix

 

[RickyD]

Assuming you installed the impeller correctly with the drive key you may have disconnected the water tube at that goes from the impeller thru the low housing to the engine block. If you drop the lower unit check the water tube for looseness if it is not sealed at both or one end you will have the problem you describe. I had it happen on a new Evenrude 25 Etec. It required removing the block to fix

So I just took out the bottom end again to check I was afraid that the outlet from the impeller housing was not perfectly lined up with the line up inside the shrouding. We were very careful to get that aligned. Still no good so then we said lets look at the impeller and it was dry and burned up. It was been running totally dry I guess. Some of the base is also screwed up. So I think when I put it in the first time we did not have the impeller outlet opening lined up with the line inside the shroud. Now its time for more parts and a redo. I'm getting good at this. Lots of practice.

 

[Flatswing]

I have the same outboard and last year I noticed weak flow. I used some thick weed wacker line and shoved it up through the pee hole, it dislodged some salt and started flowing nicely.

I have a Honda 30. I’ve gone thru all the impeller changes, pulling the lower unit repeatedly etc. disconnecting & flushing the telltale line is the solution but it is a major PITA on the Hondas unlike the Yamahas but the only solution if you have been dragging through sand while beaching/gunkholing and ingested a lot if sand. Mainly I just carry the string trimmer line too. While the motor is idling thread it up from the outlet as far as it will go, usually restores flow when removed. Even if it reblocks while underway, you know that the engine is being cooled. (Hondas alarm and go into limp home mode if they overheat or have low oil pressure). Another trick I’ve learned is to get one of the West Epoxy 10 cc syringes which have a long, fine tapered tip. Fill with salt away and inject it up the tell tale outlet with the motor off, let it sit overnight. Saves a lot of dismantling.

 

[RickyD]

Thanks everyone for your responses. I have solved the main issue. When I took the bottom end off again and saw that the impeller was grinding down I ordered an entire new kit. When it came in we started replacing all the parts and we found the problem. There is a metal plate that is under the impeller and provides a surface for it to spin on. Somehow, on the first rebuild, we left it out. Later when I was re-looking at it I could not find the box I had put the old parts in. So, next I found the box and damn, there is the old metal plate and a new one I should have put in. My only excuse is a buddy was helping me, he has experience with outboards and I let him take the lead, but yes I was looking on. So, its the captains fault. Got everything replaced but there is still some shredded impeller stuff up inside. There was a moment when I sped up the engine and the tell tail water came out very strong, now not so much. Also, if I idle for a few minutes the hot water alarm goes off. As long as I'm at about 1100 or 1200 rpm, no overheat and the tell tail water is cool. So, eventually I'm hoping that stuff will work its way out. I don't know how to get to it otherwise.

 

[RickyD]

Oh, also I squirted water down the pipes below the removed thermostat to try to blast stuff out. No change. I removed and loosened the bolts holding the water jacket cover on and I did not see any problems from there. The bottom bolt is really hard to get to so I didn't take the cover all the way off. I used some carb cleaner with the red tube to blast back into the tell tail and I did get some of the old impeller crap to come out but it didn't really improve things. The first time you try to fix stuff yourself it's learning experience.

 

[SteveK]

The simpliest thing can cause such a headache.

 

[tpbrady]

DennisB1 may be on to it. On a 25 Honda, when you drop the lower unit to replace the impeller lining up the water pump output with the lift tube when you reattach it is a pain. If it’s not properly seated, no water will reach the motor.

Tom