Chrysler Model 455HG circa 1974 lower unit?

[geason]

Bought an old boat with Chrysler 45 hp outboard unit. Put engine in water tank and got the unit to crank after cleaning the carbs but notice alot of heavy oil in the water tank now. A fearing that the lower seals are blown. How would i check / remove lower unit to replace seals and where can i get seals for an old unit like this? Might as well change the impeller also. Thanks in advance.

 

[jerryjerry05]

Re: Chrysler Model 455HG circa 1974 lower unit?

Drain the oil from the lower unit.Make sure you only remove the drain plug.
If water or anything other than oil comes out you will need to figure out where it's leaking.Usually a pressure test is needed.
Those parts can be found just look on the net.Lots of older yards still have them.J

 

[geason]

Re: Chrysler Model 455HG circa 1974 lower unit?

Have a vacuum pump or pressure pump available. What should the vacuum be set to and how long should it hold the vacuum? Thinking about buying a SELOC manual for this engine, would it be worth it?

 

[jerryjerry05]

Re: Chrysler Model 455HG circa 1974 lower unit?

Seloc or Clymer??? Any info is better than none at all.
Check pressure and vacume if you have both.8-10#pressure and it should hold as long as it is on the unit. 5-10min will usually tell if it's leaking.J

 

[geason]

Re: Chrysler Model 455HG circa 1974 lower unit?

Will check pressure hopefully tonight. Will have to rig a pressure inlet piece for the foot. Out comes my drill and tap set to make a pressure inlet piece.

 

[geason]

Re: Chrysler Model 455HG circa 1974 lower unit?

Had put new gear oil in last night and ran the motor. Drained water from water tank and then opened the lower unit screw to drain oil and oil looks like the color of a milkyway bar. I think that means water in the lower unit does it not? Ok now i have taken the LU off and noticed water and oil sludge above the water pump. I have actually taken the water pump off and the impellers look great. I think there is only two ways for the water and oil to come together and that is at the seal that goes into the LU right below the water pump or maybe the gasket that houses the water pump. The gasket housing the water pump is made of metal but looks like some one previously RTV'd the gasket to the LU also. What parts should i replace - the metal gasket looks in great condition, the impeller looks great with no cracks. Should i replace the gasket ring seal on the lower unit? if so where can i purchase this part?

 

[geason]

[B]Re: Chrysler Model 455HG circa 1974 lower unit?[/B]

Re: Chrysler Model 455HG circa 1974 lower unit?

Have the lower unit off. Notice the spline shaft will turn as it goes through the lower housing and a rubber seal with a round spring to keep it tight against the spline shaft stays stationary. To my thinking this should turn with the shaft as part of the bearing should it not? Other wise the shaft rotating at 3000 rpm would just heat the rubber seal to the point of melting. Is this correct. Should this seal be changed?

 

[byacey]

Re: Chrysler Model 455HG circa 1974 lower unit?

There are 3 seals - The prop shaft seal, the engine driveshaft seal below the water pump, and a small seal on the shift rod. As well, there's an O ring on the prop bearing carrier, and a spaghetti seal if you have the two piece gearbox housing.

Remove the lower unit and pressure test while submerged in a water tank, bathtub, etc., and where you see bubbles is where your leak is.

 

[geason]

Re: Chrysler Model 455HG circa 1974 lower unit?

Have seperated the lower unit from the gear box, what a chore that was. I finally wound up getting torch to heat the lower unit so i could pull out the bolts. Wound up breaking the long bolt - drilled out the bolt and then re-tapped the hole. The gear box seals looked good but the seal below water pump was bad. Had to seperated the lower unit from gear box to get this seal out. Waiting for new seals to arrive. Will replace the seals and test hopefully this wednesday. Thanks for the reply. Now i know i will probably have to order the O ring and 3/8" long bolt.

 

[geason]

Re: Chrysler Model 455HG circa 1974 lower unit?

I got the lower unit back together and took the boat out on the river. Runs fine but not enough power for my 15' national. Sorely dissapointed in power of the unit but glad the lower unit works. Now i guess will try to find a bigger engine. Hull rated for 75 hp so i guess i will start there. Thanks for all the help.