Water Flow - 1983 Black Max 150 Outboard

[jimbo3san]

I have a few questions about the water flow in my '83 Merc 150 Black Max.

The engine had been sitting for a while...4 years or so. We put new fuel in and lubed the cylinders over a few days with a storage lube we got from the marine shop. This procedure was recommended by the mechanic there. The engine started right up with no troubles but the tell-tale (aka pee-hole) wasn't spewing any water. We shut the motor down immediately. We decided to replace the impeller and water pump assembly. We did this, reassembled it and same result. I took one of the water tubes coming out of the head to see if water was making it anywhere up in that area. They were dry. Here are my questions:

1) When reassembling we noticed the 3" plastic grommet piece fit quite loosely around the copper tube leading up to the power head. Is this normal? It seems like this is kind of a "guide piece" to mesh the tube to the water pump?

2) I tried blowing compressed air through this tube. There was only a small amount of air coming out of the power head (We removed one of the tubes from the water connection to test this). My question is, how much air should be coming out of these orifices? In other words, I was putting quite a bit of air and pressure into the tube in the LU and only getting a small hiss out and the pressure seemed to build up inside the engine. When I took the air hose off it seemed to discharge out the LU main tube. This didn't seem right to me. But I don't know marine engines that well.

3) The impeller/water pump kit was a Mallory. I am sure it was the correct one but there were a few subtle differences on the new one vs. the old one. Is this normal? Example: there was what seemed to be a small (1/16") "weep passage way" that lead up to the drive/tranny shaft. Whereas on the old one there was no such passage way, etc.

Any input or ideas of why water isn't flowing would be greatly appreciated.

Kind Regards,


Jim B.
Forum ID: Jimbo3san

 

[j_martin]

Re: Water Flow - 1983 Black Max 150 Outboard

I have a few questions about the water flow in my '83 Merc 150 Black Max.

The engine had been sitting for a while...4 years or so. We put new fuel in and lubed the cylinders over a few days with a storage lube we got from the marine shop. This procedure was recommended by the mechanic there. The engine started right up with no troubles but the tell-tale (aka pee-hole) wasn't spewing any water. We shut the motor down immediately. We decided to replace the impeller and water pump assembly. We did this, reassembled it and same result. I took one of the water tubes coming out of the head to see if water was making it anywhere up in that area. They were dry. Here are my questions:

1) When reassembling we noticed the 3" plastic grommet piece fit quite loosely around the copper tube leading up to the power head. Is this normal? It seems like this is kind of a "guide piece" to mesh the tube to the water pump?

2) I tried blowing compressed air through this tube. There was only a small amount of air coming out of the power head (We removed one of the tubes from the water connection to test this). My question is, how much air should be coming out of these orifices? In other words, I was putting quite a bit of air and pressure into the tube in the LU and only getting a small hiss out and the pressure seemed to build up inside the engine. When I took the air hose off it seemed to discharge out the LU main tube. This didn't seem right to me. But I don't know marine engines that well.

3) The impeller/water pump kit was a Mallory. I am sure it was the correct one but there were a few subtle differences on the new one vs. the old one. Is this normal? Example: there was what seemed to be a small (1/16") "weep passage way" that lead up to the drive/tranny shaft. Whereas on the old one there was no such passage way, etc.

Any input or ideas of why water isn't flowing would be greatly appreciated.

Kind Regards,


Jim B.
Forum ID: Jimbo3san

1. It's just a guide. The seal is a rubber part in the top of the water pump housing, and the plastic tube just guides the pipe into it.

2. Most of the air would go down the leg. The two hoses at the top of the motor are connected to the thermostat housings. When the engine is cold, the thermostats would be closed, and the only air getting through would be through the weep holes in the t-stats.

3. Should work.

When you run it on the cuffs, there should be a pretty good flow through the propeller. Usually after they sit awhile you have to evict the spider family from the tell tale hose to get it to put out a stream, and then it only streams after the engine is warmed up, usually about 30 seconds.

If you get a lot out of the prop, and none through a known clean tell-tale, you might have to service the poppet valve, located on the starboard side, low.

hope it helps
John

 

[jimbo3san]

Re: Water Flow - 1983 Black Max 150 Outboard

John,

You were correct. I started it, with the LU submerged in a garbage can of water, waited about 45 seconds and it started to spurt water. It was actually quite a strong stream too.

I was afraid to run it more than 10 or 15 seconds fearing it would severely damage the engine. That is often what I heard is that you can't run them at all w/o water or you will toast the heads. While I am sure that has merit to some degree, running it for 45 sec - 1 min produced the heat and subsequently the water flow through the Powerhead.

Thank you sincerely for your input!

Cheers,


Jim