1979 Mercury 40hp 2 Cylinder - Help

[huntingbronco]

Well guys, you both make great points. I have come so far and the coin for a new motor could set me back a year. I'll try the float thing and try to figure out where the thermostat is...

I was kind of thinking that if the compression is down between 110-120, it might not be worth much more effort, but you guys make great points about being able to chase the two key issues - float and coolant water.

My work on my 1968 Montgomery Ward Snowblower went well tonight, so maybe things are going to turn around.

 

[wasilvers]

Compression at 110-120 is fine - the motor shoud run on that. When you have fuel/oil, I always beleive it compresses better than testing when 'dry'.

 

[Kago5938]

That may be known as a Merc 402 what I found works to get it to pee with more pressure is a piece of silicon hose to join the metal water tube with the nylon one that sits on top of the water pump. I have some from a hobby shop packaged as replacement tubing for a Dave Brown 6 shooter fuel pump for RC planes also Traxx silicon exhaust tubing for RC cars.

 

[Kago5938]

Getting compression back- if possible get the motor positioned spark plugs vertical remove plugs set the pistons at TDC using a screw driver to check it pour in the plug holes Seafoam straight to the top screw the plugs back in check the level over the next few days top it off. Walmart and some automotive stores carry it.

 

[huntingbronco]

Kago - you are talking about where the water pump hooks up to the metal pipe riser that goes up to the bottom of the engine from the lower unit, right? Does this stop leakage at that location or just give flexibility for a better fit/alignment up top? It has been several months now since I did my water pump - can't say I recall what it looked like. I just know that everytime I ever try to get the water pipes on any outboard lined back up, I have no confidence that they have actually sealed. There has to be a better way to connect water lines...

 

[huntinfool]

Before I put a lower unit on I put grease on the tubes. This will help them slide inside one another. Remember, just because you have replaced something does not guarantee that it is perfect.
Like I said we work on boats for a living. (mostly fiberglass, but some mechanical) And I have done several WP's. But I had one I just put together 3 times and it failed twice. NOT because of something we did wrong, but because of trash below the pump it ate the impeller up. We would put the water to it and pump the trash back through it and eat the impeller. Luckily we caught it and resolved it. So you could easily have had a problem similar to that and not even know it.

Also, the compression range your saying is just fine. I have run outboards at 95 psi on all cylinders and they ran great. So I really think your just fine there. Keep us updated on where you are and I am confident that we can help get your outboard running.

 

[huntingbronco]

Can someone explain to me what sticking reeds and a dry cylinder means? Can sticky reeds be repaired by soaking in seafoam, similar to the suggestion about filling the cylinders with seafoam?

 

[huntinfool]

The reeds are basically a one way valve, that let the fuel into the cylinder and not out during the compression stroke. While the cylinder is on the downstroke it allowes the fuel to be sucked in through the reeds and on the compression stroke, they close and do not allow the compression to blow back through the intake and carb.

A dry cylinder is just that. Dry. No fuel and more importantly no oil. That is why we always suggest when someone says they have a motor that has been sitting for a while, to remove the plugs and "lube" the cylinder.

Are you still having troubles? Where are you at in the repairs? What have you done out of the suggested ideas?

 

[huntingbronco]

I have pulled the motor off the boat. I am going to soak the powerhead with seafoam and take the needle above the float out. Then I'll bench test to see if it will run.

When I started with the motor, I think I shot the cylinders with oil...but nothing like soaking in Seafoam. Does it make sense to flip it over and soak the bottom side in Seafoam?

 

[Derek]

having any luck?

 

[huntingbronco]

Yes-I have to get some pics up of us on the water with the boat. I ended up stumbling into a good deal on a 1980 40 hp merc. So I swapped engines and controls and away we went. Now I have to decide whether to tinker with the 1979 or sell it to some enterprising individual. We got loads of compliments on the finished boat.

 

[Derek]

awesome get some pictures up

 

[huntingbronco]

Pics of boat with replaced motor on posted on the boat project page, rather than here. I won't work the camo painted '79 until this winter, if I don't sell it first. Price will triple if I get it running right!