Volvo sp-c gear housing temperature

[ashewitt]

I was in the process of brining my boat out of winter storage. It has a 4.3 engine and a SP-C outdrive. I hooked it up to the ear muffs and it started up without any problems. I wanted to let the engine get up to temperature so I engaged the drive in forward and let it run at around 2000 rpms for 5 minutes or so. Eveything looked good. While I was checking the out drive I found that the upper gear housing was getting pretty warm. Maybe the temperature of a hot cup of coffee. I just need to know if that is normal. If not, any ideas what would cause that to happen. I just had the unit pressure tested and the gear oil was replaced last year.

Thanks in advance.

 

[RicardoMarine]

Some heat at the transmission would be considered normal.

The SP-C drive will have a slinger pump in the lower unit.

While engaged in gear, this slinger pump will operate.
This is a centrifugal pump, and is intended for engine oil, not heavy gear oil.
Under normal operating conditions, this pumps the cooler lower unit oil up to the transmission for cooling, then it gravity drains back to the lower gear unit.

Since you ran the engine while the transmission was engaged, both the lower unit and the transmission should have been close to the same temperature, IMO.

Heavy gear oil may occasionally shear the centrifugal impeller drive pin(s) off.
If we loose the drive pins, the impeller will not pump oil.

If you've not re-sealed the lower unit in a while, now may be a good time to do so.
While you're in there, you can check the slinger pump.


If you are fairly mechanically inclined, this is a user friendly task.
No changes will occur to any shim values, so long as you re-install the shims as they were.
IOW, it would be pretty hard to mess up!


.

 

[ashewitt]

Thanks for the information. Additional info. This outdrive is the same one I am having problems with sticking in forward gear after a long run under load. Now I'm thinking it may be an overheating issue. Also the case is filled with motor oil now. It may have been gear oil prior to that so sheared pins is a possibility. Now I have some more things to try. First I'll bring the engine up to temperature again with the drive engaged. If I followed you correctly the transmission area and the bullet area should both be about the same temp. Also along the same lines if I cool the lower unit with water the transmission area should also cool down some. Can I remove the top cap from the tranny and see oil circulating or would that be a total mess? After or before doing any of that is there any other way to test the posibility of the broken pins on the oil pump? Then finally where would I find a guide on replacing the lower seals. I think I'm inclined enough to give it a try if needed.

Thanks again.

 

[RicardoMarine]

Back to you........................

Thanks for the information. Additional info. This outdrive is the same one I am having problems with sticking in forward gear after a long run under load. Now I'm thinking it may be an overheating issue. Also the case is filled with motor oil now. It may have been gear oil prior to that so sheared pins is a possibility.
It is possible.


First I'll bring the engine up to temperature again with the drive engaged. If I followed you correctly the transmission area and the bullet area should both be about the same temp.
Only while out of the water and on the garden hose. Once in the water, the lower will be cooler.


Also along the same lines if I cool the lower unit with water the transmission area should also cool down some.
No need to while out of the water..... there's no load on the drive.

Can I remove the top cap from the tranny and see oil circulating or would that be a total mess?
It will cost you a new special top cover gasket....... and all three gears are turning anyway, and oil will be splashing around.


After or before doing any of that is there any other way to test the posibility of the broken pins on the oil pump?
None that are scientifically proven.

If you could find a way to spin the prop shaft while in neutral (engine off), you may be able to see oil movement via the transmissioni fill port.
When you spin the prop shaft, the slinger pump should be rotating and pumping.
Nothing above that, but the vertical shaft and sliding sleeve, will be turning.

Then finally where would I find a guide on replacing the lower seals. I think I'm inclined enough to give it a try if needed.
See your Volvo Penta OEM work shop manual... not Seloc.... not Clymers.

It is fairly easy, but you'll need a prop shaft bearing carrier pulling tool.
This is my design. It's drilled for both the s/p and Duo Prop lowers.
Plate is 1/2" steel, threaded rods are grade #8 7/16" NC . (anything less than grade #8 may bend)