starting and water problems 72 evinrude 100

Ok so I dropped the LU last week to rebuild the water pump because the motor wasn't circulating water. well the impeller looked brand new, the vanes hadn't even set yet. Well I put the new one in anyway and put LU back on.
Tried to start it and it would fire and start, but slowly die. Or start to slowly die, then misfire(through prop not carbs) and die completely(see question about this below) . I got it to run for about one minute finally, and it still wasn't pumping much water. There was hardly any coming out of the holes above the cavitation plate, and a bit of a spray coming out the exhaust relief.
There was a very fast stream of water coming out of the lu thru a little hole at the very front.

I don't think any water was getting to the powerhead. I know its possible I aligned the water tubes wrong, but how are you supposed to align them right?
By the time they meet with the pump tubes, the pump is in the way of adjusting them.

On a side note, I removed the t-stat because i thought that could be the problem since the pump was in good condition, so we can eliminate the t-stat for water blockage problems.

My other question is now why does this motor not stay running when it ran perfect a week or two ago. I did remove the carbs and electronics to repaint the powerhead, but I doubled checked the wiring and it's all correct. The carbs were cleaned about week or two ago.

Thanks very much for reading the long post guys!
Very much appreciate it!
Dog

Here are some pics of the motor. If i can get it to start running good again will be going on a friends bay boat.

Re: starting and water problems 72 evinrude 100

Did you find the plastic guide tubes for guiding the water tubes into the pump grommets? They are usually shinnied up the water tubes. Pull them off the water tubes and stick them into the water pump. Enter water tubes into the plastic guides while you can still see them and the rest takes care of itself. BTW, oil the grommets so the water tubes slip in easy.

Put the thermostat back in. Did you also remove the relief valve from the 'stat housing? tch tch.

They don't put a huge amount of spray out the relief holes.

Re: starting and water problems 72 evinrude 100

The coils are color coded for each cylinder. You may have a coil wire crossed. Check the factory service manual wiring diagram. That would account for the occasional backfire. When you run the engine, temporarily remove the water hose (to the thermostat housing) from one head, then the other. You should get a flow of water of each head. Personally, I would put the vernatherm back in the thermostat housing. You can do long term powerhead damage from carbon buildup if the engine runs cold. If the engine overheats (at 212 degrees,) you will get a horn. You made no mention of a hot horn. If you hold your hand behind the exhaust relief holes in the upper midsection, water droplets will form on your hand when the vernatherm (thermostat) opens.

Re: starting and water problems 72 evinrude 100

I will drop the Lu and try re-adjusting the water tubes. When I removed the t-stat i did remove the relief valve too. I'll try reinstalling both.
I will also double check the coil wires. Last week when I ran the engine on the muffs it did give me the hot horn after which i immediately shut it down. It wasn't pumping water which is why i replaced the impeller in the first place.

Re: starting and water problems 72 evinrude 100

i got a 70 115 hp. Looks like yours. Does yours have the electric shift control? I'm not sure if I'm suppose to remove the insulation wrap around the two wires before dropping the lower unit or will that pull down with the lower unit? My alarm started going off last week at WOT only. Yesterday it started going off periodically almost right away tubing. Sometimes I would shut the motor down for as little as a minute and it would be good for a while, other times I'd have to shut it down for for a few minutes. So I'm going to change the water pump.