Yamaha 40HP (3 cycl), powerhead stuck

[jeroen1978]

I've got a Yamaha 40HP, 3 cylinder outboard engine from 1984 which has a powerhead which doesn't come loose.

I want to remove the powerhead for replacing the seals at the water seal housing at the bottom of the powerhead.

I've already removed the 8 powerhead bolts and I've disconnected everything but the engine is stuck, it's going nowhere.

It seems the powerhead is stuck at the gasket or dowel pins, it also won't move sideways.

A Yamaha-dealer said it's possible to remove te powerhead without removing the lower-unit so the lower-unit is still on.

Can somebody tell me how I can remove the powerhead without damaging the aluminium parts?

[99yam40]

look for places to pry with a big flat bladed screw drive or pry bar.
once broke loose it should come easily

[jeroen1978]

Tried to remove the lower-unit, what a disaster.

4 bolts at both sides came loose but de bolt underneath the anode snapped off.
Bolt is stuck because of aluminium oxide.

Tried to pry with a big screwdriver but at the front side of the lower-unit there's a very tiny gap, at the backside where the snapped off bolt is, it doesn't give a gap.

Can somebody tell me how to loosen this snapped off bolt or how to remove the lower-unit?
The bolt seems to be stuck at the place where is no thread.
And I expect when the lower-unit is off the snapped bolt will come loose easily.

[jeroen1978]

@ TownsendsFJR1300 =>"If the bolt that broke, the head, that retains the LU will NOT stop the LU from coming down"

Do you mean that the snapped bolt is not the cause that the lower-unit won't come off?
If you pry at the front you can see the lower-unit stays shut at the side where the snapped bolt is.

The shifter linkage is already loose.

Here's a picture of the snapped bolt:

[url=https://postimg.org/image/ys5cyy28t/]

[pstephens46]

Threads should be farther up. Can't remember how long that bolt is. You should be able to drill without harming anything. With the correct size bit of course.

Blast the remains of the bolt with a torch after the lower comes off.
That should definitely help with removal.

[panasonic]

From the looks of the other empty hole which has a good amount of corrosion you got a fun job ahead of you. The bolt is broken off under flush of the top of the hole...correct? The corrosion in the hole is nipping the shank of the bolt very tightly now.
BEFORE going at it with the drill I would take a heat gun and heat the area where the bolt is till good and hot then spray with WD 40, let cool. Then using a block of haRd wood up against the housing where the broken bolt is, smack the hard wood with a hammer. DON'T hit the LU directly with the hammer, or you will be buying a new one. Repeat, heat, WD 40, shock with hammer and wood, over and over.

After doing this you may try driving some plastic or hardwood wedges in joint between the LU and leg. Be patient.

If there is anything left of the head, on the shank of that bolt, you won't get the lower unit to come down. Drilling it will then be your only option. If you are good with a drill...have at it, if not bring it too a machine shop and let them drill it out.

Sometimes just a hole drilled in the center of the bolt shank, about half the size of the bolt will relieve the pressure in the hole and it will let go...

Hopefully driveshaft is not rusted into the bottom of the power head as well...

[exeter27]

Assuming that picture is of the lower unit anode and 'directional vane', just ahead of that part is likely another bolt that goes from the lower unit into the mid-section. I'll just say that I've overlooked that bolt before - and gentle reminders from others had me look for that additional bolt. You likely have removed it...but just in case it was missed, I'll mention it.

[jeroen1978]

I've been working at the outboard engine yesterday but again without any result.

I've heated up the bolt with a solder heat gun, spraying penetrating oil while heating, no result.

I've smacked the lower-unit with a rubber hammer, without any result.

Tried to drill a hole into the center of the bolt but I couldn't, the propshaft is in the way so I can't drill into the center.

I want to try the heat and freeze method.

Can somebody tell me which part I have to heat and which part I have to freeze?
Heat the bolt and freeze the aluminium around the bolt or heat the aluminium around the bolt and freeze the bolt?

[jeroen1978]

Yesterday I've been 10 years older in 1 day time but I've managed to get the lower-unit off.

We drilled out the snapped bolt and after some punches with a rubber hammer en prying with a flathead screwdriver the lower-unit came loose.

After that we could remove the snapped bolt with a plier (grip) so we can re-use the thread, see picture below.



Only a pity we didn't drill straight, now there's a small hole in the alunimium, see picture below.



For mounting the lower-unit it wouldn't matter, only I have to seal this hole because the water can reach the bolt directly so I must look how to close this hole.
Somebody has a good idea for that?
I've got a tube of gasketmaker for sealing parts which are in contact with water/coolant.

After prying with a prybar finally the powerhead came loose.
It seems that the plines at the drive-shaft have never been greased but they look clean like a whistle.



The big oilseal is indeed damaged, I hope that the crankshaft-bearing is not damaged to much.
The brown dirt at the cage of the bearing seems to be burnt oil, see photo below.



What's your experience when you see this bearing?
Is it good to put some grease into this bearing?
If yes, what kind of grease should I use?

Now I'm wondering what type of material the snapped bolt is.
It's a bolt M8 with a length of 90 mm (from the top of the head to bottom) and when you use a magnet pickup tool the bolt sticks to the magnet so it's no stainless steel.
Can somebody tell me what kind of bolt (material) this is?

In the servicemanual I read they use Yamaha Grease A.
Can somebody tell me what kind of grease this is and which grease I can use instead?
I want to lube oilseals, the crankshaft bearing, the plines at the driveshaft, the propshaft and al bolt against corrosion.

[99yam40]

need to make sure that brown is not rust powder

[jeroen1978]

No big update's yet.

I was afraid I had removed the powerhead and lowerunit for nothing but I'm glad I did it, the lower oil seal was faulty.

The big oil seal was very bad.



I've already got the new oil seals, O-ring and a new bolt (for the one which snapped off) via a friend who works at mechanisation company, so no expensive original parts.

Now I'm still waiting for a cylinder of marine grease which must come from the same friend.

I need a new gasket between the powerhead but the original is very expensive so I want to try to make a proper gasket with Reinz gasket paper.
If I don't trust I'll buy a cheaper aftermarket gasket.

There's a short crack and the half of the hole in the oil seal housing broke off while removing it from the powerhead (it was very stuck) so I must look if it's possible to re-use this part.



I'm going to cut the pipe untill the crack ends (the half of the pipe).



And I'm going to look if I can still tighten the oil seal housing with the original screw.
Else with a bigger washer.

Question about the oil seal housing.
According to the servicemanual you have to lube the O-ring and you must apply some gasket maker.

Do you have to place some gasket maker at the edge of the oil seal housing (see red circle)?

[boscoe99]

Why would you not replace the cracked part? I see a section of it that is also broken off.

[jeroen1978]

The oil seal housing is placed in the openening you can see at the picture below.



The oil seal housing has an O-ring for sealing the oil seal housing/powerhead.

[99yam40]

the split case forms that hole the housing sits in.
I would use a small amount to make sure the seal is good.
service manual should say what Yamaha recommends.
hopefully the 2 sides of the case meet well to form a perfect round hole.
I think I put that housing in before tightening the case bolts to make sure

[pstephens46]

What would cause that damage? Hitting a coral reef?

Or one of Hillary Clinton's ankles?