Need help with my 50hp boat outboard

[Pinhead]

Hi guys, I’m having a problem pinpointing the issue with my 1992 2stroke Nissan 50hp tiller motor. I’m not getting water up to the top and out the drain hose. I changed out the impeller but still no water. What happens after the impeller? Does the water continue up the water pipe into the head and then expelled out the drain? I had help with someone knowledgeable about impellers help me change that, so let’s assume that’s not the problem.

What else could be wrong. The water pump system looks relatively simple, what am I missing?

Thanks,

Dan

[petew]

Weeds pluging the water channels ? Try a reverse flush with a hose to clear the water jackets and passages.

[Pinhead]

Thanks for the reply. We tried that and had water dribbling out the bottom intake.

Dan

[petew]

Originally Posted by Pinhead

Thanks for the reply. We tried that and had water dribbling out the bottom intake.

Dan

There should be more than a dribble I would think. The only thing to do is flush and clear the passages. Does it have a thermostat? if so it can be pluged. You have to open the passages . Are you sure the impeller drive is not also broken?

[Pinhead]

Looked at the thermostat, thought it would work regardless. Am I wrong?
New impeller in and that part I believe to be good.

[petew]

If the thermostat is stuck closed it won't flow, , and it also won't open until the motor is hot.

If it was mine I would pull the thermostat, test it in a pot of boiling water , or over a candle to make sure it opens when hot or just replace it without testing it. While you have it out do some flushing to make sure there isn't any restrictions from weeds,sand,or old impeller pieces.

[58thecat]

Yup go thermostat.....if crap got up there it will act up....pull, clean, inspect.....replace if suspect....

[pikergolf]

Pull the thermostat and reassemble, run like that and see if you have water. If you do thermostat is faulty.

[Half Pickereled]

Originally Posted by Pinhead

Looked at the thermostat, thought it would work regardless. Am I wrong?

New impeller in and that part I believe to be good.

Not necessarily, some do and some don’t have a steady tell tale stream...old v4 Evinrudes will have a steady stream no matter what. But for example a Mariner 15 hp will only flow when the thermostat is open so it’s intermittent and can make a grown man faint if he’s not aware of it.

If you have access to a temperature gun.... run it and zap all around the water jackets and see what temp your running at.

[jungleboy]

Are you sure you have the water line from the pump properly connected to the one that goes to the powerhead? They can be tricky to line up sometimes when you are re attaching the lower unit.

[barbless]

A couple times I've had to push a wire in the pee hole line cause it got blocked by some crap in the water. Only takes one day of sitting for it to plug. If you can get at it from both ends that's a bonus. I blame it on thick algae blooms. Have had to do my 150 2 stroke and the 8 hp kicker. Now when I get home I run the clean water through and flush both clean. Try cleaning that line out in the middle of a wavy lake

[Pinhead]

Thanks for the replies guys. I’m going to try some of your suggestions, I’ll let you know how I make out. There may be others that could benefit from this thread.

Dan

[Pinhead]

Ok, verified by hot water the thermostat is working. I guess it could be intermittent but I opened and closed it a few times and it worked everytime. I think the next step is to take the lower leg back off and check the water pipe physically for any obstructions.

Dan

[bagwan]

When you have it opened up again blast some air through the water pipe. I had a spider nest in a smaller engine and that was the only direction I could blow out the obstruction. Hopefully its just the pipe not lined up.

[petew]

Originally Posted by Pinhead

Ok, verified by hot water the thermostat is working. I guess it could be intermittent but I opened and closed it a few times and it worked everytime. I think the next step is to take the lower leg back off and check the water pipe physically for any obstructions.

Dan

That's one thing eliminated. It is entirely possible that all is good. With the thermostat closed on a cold engine only a trickle of water gets past. Usualy the thermostat has a small hole in it so the heads are not dry. Can you run it at idle in a drum of water with the thermostat removed ? or run it with the thermostat in , let it heat up to operating temp, and see what flows? If so just monitor the temp and don't let it overheat.

Good luck.

[barbless]

From what I've heard you don't want to run too long without water coming out where it's supposed to. That could cause you another whole world of grief. The water line connected in the leg might be. Some can be tricky to line up. I only know from talking to marine mechanic and research.

[Pinhead]

Yes, it can be tricky to line those up. Still working through this issue. I thought I had it figured out yesterday but it turned out that I had not lined up the water pipe with the lower leg right. I’ll be back at it tomorrow. I must have taken the lower leg off 12-15 times now. You would think I’d learned by now to make sure it’s lined up. But if I’m working alone it can be tough. Not only must the water pipe line up but so must the gear shifter and main propeller shaft.

Thanks for the suggestions.

Dan

[barbless]

I did see a good video a while ago but don't remember what site. There are some good ones out there, just have to find the right one. I remember the guy talking about how tricky it can be and he gave some good hints on how to do it. Good luck. With a few choice words it usually works.

[barbless]

Ok found one that might help. Go to your search bar ( Google or Bing ) and put in " how to line up lower leg on outboard after replacing impeller" when it comes up pick the youtube video done by Dangar Marine. This could help cause he also does it by himself. Hope it works for ya

[Pinhead]

Ok, now it is working. Took the lower leg off and carefully put it back on. Ran it for 10 mins or so fine. I’m running it in a garbage can. But, when the water got below the ant ventilation plate the upper water stopped. I topped off the can and everything is good again. Any ideas why ??

Dan

[barbless]

In a garbage can could be too much cavitation. 45 gallon drum better but hard to put a 50hp in if motor not on a hoist. That's what I use for my 8 horse kicker. How about hooking up the muffs and the garden hose. I use that for my 150 2 stroke. They make single side and double side feed of water. If you got all hooked into place you should be good to go. Try the muffs. Cheap to buy

[Pinhead]

Got it finished. Just a matter of lining everything up well. Even though it took me a bit to figure it out this is a job the average boater with a little mechanical experience can handle.

Good luck, thanks for the help AO.

Dan