Water Cooling Repair - Yamaha 5hp Outboard

[landonshaw]

I have a 5HP 2001 Yamaha outboard motor that stopped running. Investigating I say that there was no water flowing out of the engine. My first thought was that the impeller broke. I took the lower casing with the prop off and found out that the impeller was good but the copper tube from the impeller up to the engine had broken at the seal to the engine.
The problem is that I have taken the 7 bolts out to remove the entire lower casing and it will not drop away from the engine. Does anyone know if there are other bolts that need to be removed. I have placed a piece of wood on the lower casing and hit it with a hammer, it does not seem to budge.
Suggestions? thanks Dave

[motion30]

When you say lower casing do you mean the lower unit? If so there may be a shift rod to unhook Sometimes the driveshaft can get stuck in the splines of the crankshaft This is a problem Turn unside down and get some penatrateing oil down there let sit a bit Becareful as it is easy to break the casting

[landonshaw]

yes lower unit. I have the shift rod unhooked and the drive shaft is out. These came out when I inspected the impeller. On the Yamaha, you unhook the shift rod and unscrew a couple of bolts jsut above the prop. Then pull the prop off of the lower unit. The copper tub should remain attached to the engine, in my case it had broken off. I am now left needing to remove the casing that extends from the engine down to the unit that holds the prop.

On the yamaha web site it looks like there are 7 bolts that hold it in place. Remove this and there is acess to the copper tube that attaches to hte engine.

that may not be true though given I took off the bolts and nothing moves.

[motion30]

so the impeller is behind the prop? You removed the propshaft All the bolts are out of the lowerunit but it will not budge? Make SURE all the bolts are out sometimes there is one under the cavation plate so its stuck, most times the splines between the crankshaft and the driveshart are corroded Try shake and wiggle the unit while holding the motor if you can get a small gap try some small wooden wedges This can be difficult and not always successful I have seen motors destroyed trying to get apart, good luck

[landonshaw]

I have tried to attach the outboard picture of the engine. The lower section, from the housing down is the part I am trying to remove. The engine has a model 5CMH printed onit, although it does not appear on the Yamaha website.

[landonshaw]

Looking closer, it seems that there are 7 bolts and an addition 4 that need removed. Anyone know if the engine needs to be lifted out to get to the top of the copper tube that runs from the impeller up to the engine to cool it?

[motion30]

The pic helps
Take off the coweling there are bolts under there that need to b removed What you want to do is pull the powerhead Unhook fuel lines an some electrial when all the bolts are removed it wil come right off and you can access the copper water tube new tube , new gaskets you are back in business

[neilpride]

Ok, i have a 5 yamy after some idiot stole my 10 4 stroke in Stlucia, and i dismantle this engine 2 times to change 1 seal at the cranshaft and the 2 time for cowling sal deposits.
Take off all the 7 screws holding the engine to the top cowling , carburetor off, and becarefull because the electrical coil and wires are screw it to the engine and the cowling to, so you need to unscrew 2 bolts from the engine or the cowling,
now, there is 2 gaps at the gasket level in the engine , you can put a flat screw driver in this gap and other in the other one and make a catapult pull smooth to detach the engine from the bottom , i dont recomend to use sharp screwdrivers in the gasket section, you can damaged the aluminium surfaces, just a couple of taps taps to move the thing 2 mm or 3 , with 2 persons are easy one pulling from the leg and the other from the flywheel , with the engine off, you can see now the end of the cooper tube in the casing with a rubber gromet in the casing. Easy to replace...
Take the chance now to clean the salt deposits, gaskets surfaces ... Hope this help, good luck.

[landonshaw]

Thank you, off to see what I can get done.

[Kapena]

Landon...Why do you think this will make the engine run? Did it run once it is cooled off?

[landonshaw]

yes it did. Before looking at the impeller, I started it and then shut it off immediately when it started. This was after I rowed back to the boat. It was cool and I was hot. So a cold beer cooled me off but didn't help the motor.

[Blue Stocking]

Uh Oh! I hate to rain on your parade, but seeing that CMH code does not bode well.
I have scoured the net, in multiple languages, to find some info and parts on a 2CMH.
They seem to be some bastard assembly of Tohatsu parts ad infinitum,
That nobody seems to know anything about.
Have frustratedly dealt with dealers in a number of countries--only to recieve blank stares in return.
AAMOI, I am looking for the 3 electrical components which make up the ignition system on a 2005 2CMH.
Man!! I wish you luck.

[landonshaw]

Well I got everything off and then back together. Started the engine for a few seconds in the garage wash tub. Water came out of the recirculation spout!

The hardest thing was getting the prop section back on the outboard. There is the control shaft, water tube and drive shaft that all need to get aligned and put on. It took the longest to do that.

Also, besides the 7 original bolts I took off a few more, fuel tank had 2, and there were two others, then the engine came out easily. Had to disconnect gas line and engine control arm also. Did not have to drop the lower casing, with the engine off, I was able to attach the new copper water tube.

So, thanks for the pointers. Off to the boat. Dave

[Kapena]

Blue...Nissan and Merc might be the same motors as this. If you buy Nissan parts they are cheaper then the Merc parts though exactly the same. I have bought a Yamaha impeller for my Nissan 5hp and also a merc prop (must learn to stay out of the coral).

[foxinsox8]

So it's eight years since you wrote this Dave and I have the same motor, same problem. Taken out all the obvious 7 bolts but can't separate the bottom of the power head from the plate at the top of the outboard leg/shaft case. So how did you do it? In your last par you refer to the engine control arm ?? the tiller? or just the throttle cable?
and which bit of the fuel line.. and
cheers Tim

Originally Posted by landonshaw

Well I got everything off and then back together. Started the engine for a few seconds in the garage wash tub. Water came out of the recirculation spout!

The hardest thing was getting the prop section back on the outboard. There is the control shaft, water tube and drive shaft that all need to get aligned and put on. It took the longest to do that.

Also, besides the 7 original bolts I took off a few more, fuel tank had 2, and there were two others, then the engine came out easily. Had to disconnect gas line and engine control arm also. Did not have to drop the lower casing, with the engine off, I was able to attach the new copper water tube.

So, thanks for the pointers. Off to the boat. Dave