No power after hot shut down & restart

[iplayfarmer]

I'm a newbie to this forum and to boating, and now I need some help. I got an old hydroswift boat with a 100 HP 1963 mercury outboard (serial number 1540418) as a trade for a camper this spring, and I finally got around to taking it out on the lake.

I was warned by the previous owner about this problem, and now I've experienced it myself. The motor starts great, and runs just fine for as long as I keep it running. If I shut the engine off after it's warm, it starts fine, but lacks power. When I shift into gear (forward or reverse) it bogs down and dies.

I can usually do engine work, etc. myself; but I don't have any experience with these 2 cycle outboards. Any recommendations where to start?

Thanks in advance for any input.

 

[Showtime22]

Re: No power after hot shut down & restart

Does your engine have a shift interrupt switch that is killing the motor when you shift?

 

[iplayfarmer]

Re: No power after hot shut down & restart

Does your engine have a shift interrupt switch that is killing the motor when you shift?

It would be nice if it were that easy, but I doubt it. It's not acting like an interrupt switch. It actually runs after I shift. It seems it just can't provide enough power to keep the engine running with the load of the prop on it. Any engine I've had a safety switch problem with dies immediately. This one actually gives it an effort and then dies.

I'll have to look into it and see if there's some kind of neutral switch just to make sure.

 

[Showtime22]

Re: No power after hot shut down & restart

If the motors health is entirely unknown to you - I'd do a compression test first. I just got a universal tester from sears for 30 bux.

Then I'd check the timing.

 

[iplayfarmer]

Re: No power after hot shut down & restart

I was hoping this would be one of those "anyone who has run an old outboard knows what these symptoms are" type of a problem, but it looks like it's not. My plan from here is to go through the "awakening a sleeping outboard" FAQ suggestions since it seems to cover the basics.

My first question here is in regard to the water pump. The FAQ suggests replacing the water pump, but I'm having a hard time finding a water pump for this old of an engine. I can get an impeller, but no full kit. What do I look for when I have it apart to tell if I need the rest of the kit?

I also bought a compression tester today per Showtime's suggestion. I figure it's about time I own one since I do enough tinkering on other engines.

 

[Showtime22]

Re: No power after hot shut down & restart

If you take the impeller off you'd look for torn, worn or broken rubber fins.
I'm not the best outboard guy but if you remove the impeller to check its condition it's probably worth replacing since you have it apart. I think there is a discharge of water from most outboards that indicates the impeller is working.

On my out drive the impeller looked bent like a pin wheel after it came out. The rubber ends are worn and bent back the way it spins. The new ones start out straight ended. The first time I changed mine - I thought I had bought the wrong part. I think I've read that its a good idea to change the impeller every 2 years.

The word water pump may mean impeller in some cases. I've said water pump and meant impeller.

 

[iplayfarmer]

Re: No power after hot shut down & restart

This may not be THE problem but it's definately a problem.

I took the bottom end of the engine unit off to get the to water pump and the rubber boot that seals the water pump to the upper tube is all scrunched inside the water pump outlet. I've attached a picture. Sorry about the poor focus in the pictures, I forgot to switch the camera to macro mode.

The other picture is of the same rubber boot part and the corresponding black tube that was above it. What is this broken part called? I looked at the parts section in cooling parts, but none of the parts looked like this one. I've looked for a manual for this engine, but there's nothing pre-1965 for this size of engine.

 

[iplayfarmer]

Re: No power after hot shut down & restart

Here's a quick followup about the compression test, etc.

I have about 85 psi on every cylinder. The compression doesn't vary more than about 2 PSI from one cylinder to another.

I also replaced all of the spark plugs. I have good spark at all of them.

 

[iplayfarmer]

Re: No power after hot shut down & restart

My level of respect for anyone who works on boat engines just increased about 5 fold. I've replaced engines in motorcycles, rebuilt transmissions in tractors, and refurbished numerous riding lawn mowers. Outboards are a whole different animal.

I got the boot that connects the water pump to the copper tube. I know that my baling wire shepherd's hook method for lining them up with each other works without kinking the boot because I had it apart and back together no less than seven times. Each time the boot was neatly seated in the water pump with no kinks, cuts, or pinched spots.

I promise I was careful taking apart the motor, but somehow the shift mechanism moved. To compound problems, I dropped a nut down inside the housing during one of the reassembly attempts, and when I tipped the housing upside down to get the nut out, the cam that locks the motor against the transom in reverse fell out. There was some trial and error getting the cam lined up. There was some trial and error getting the shifter to snap into the right place when putting the motor back together. There's a certain set of words that seems to be the only thing a motor understands in situations like that.

I did replace the impeller for the water pump while I had it all apart. That was the easy part.

My dad is coming over this afternoon, and we'll take it for a spin on the lake to see if the problem is fixed. I'll post back whether the problem is fixed or not. I won't be surprised if the problem persists. That would just be my luck.

 

[iplayfarmer]

Re: No power after hot shut down & restart

The good news is that I got everything back together right since the boat works like it did before I took it all apart.

The bad news is that after I got everything back together right the boat works just like it did before I took it all apart.

I was more observant this time, and realized that the boat has a hard time getting started in all situations. It's like it lacks power at low RPM. If I can bump the prop into gear a few times just right and get the boat moving a bit, I can get the prop to kick in and we're off and running again.