1990 7.4L 454 w/ Volvo outdrive problem

[boatddreamer]

Hello everyone,

I am am considering buying a boat that has some motor/propulsion problems. Although I am mechanically inclined, I am relatively new to the boating scene and need some advice on what I may need to do to fix the problems and what information I should obtain from the owner to correctly diagnose the situation.

According to the owner, the boat had a problem with a gimble bearing (what is this?), which led to other problems. Here is the owner's description of the situation:

"When the gimble bearing failed the universal joint on the drive shaft failed and distroyed the bell housing and the bellows on the outdrive. This allowed water to enter the engine compartment. The engine compartment flooded up to the valve covers on the engine. No water entered the engine. The shaft also knocked the engine's cooling water intake hose loose and the engine ran hot just long enough to burn a hole in the Volvo rubber muffler. The engine was run after the mishap and then pickeled. No damage seems to have been done to the engine but there is no guarentee.

As a result of the flooding there are a number of electrical components that will probably need to be replaced. I will attempt to list the items I can think of but do not interpret this as a complete list. There may be other items affected by the flooding.

Gimble bearing, bell housing, main drive shaft with universals, bellows, and other components required to reassemble.

Engine starter, batteries, battery switch, battery charger, fresh water pump, water heater element, trim tab actuators and all associated wiring."


Based on the above information, I am trying to estimate the cost for repairing the boat. I am assuming the worst case scenario where the engine and outdrive will need to be replaced/repaired.

So far, I believe that the two major components of the "drive train" are the motor (a 1990 454 7.4L 330HP) and the outdrive. Is there anything else?

Any comments or advice would be appreciated. Thanks in advance!

[gonzo]

If no water had entered the engine, there would have been no need to pickle it. Is this a carburated or fuel injected engine? All electrics need to be replaced, or they will eventually give you trouble. Also, the upper unit in the outdrive is probably damaged too. Another problem with flooding, is that the rear and front crankshaft seals usually fail. The reason is that the surface rusts and breaks the seal lip. A properly rebuilt engine is as good as new; we do them routinely. Also, a rebuilt transom assembly and drive could save you thousands of dollars.
The 7.4 engine is no longer manufactured. However, the new 5.7Gxi has the same power with much less weight. We sell both new and used engines. Also, a PCM can be a appropiate replacement. But it needs some bracket and engine mounts modifications. You can check prices in my website for engines, drives and whole packages. boatwrench.net
I suggest you get a surveyor to check out the boat. It is cheap insurance to find out if there are any other problems.

[boatddreamer]

Thanks, Gonzo, for your advice. In general, should a project such as this one where I may have to replace the motor and outdrive be done by a professional marine shop or can it be done economically by a home mechanic type person?

[gonzo]

Replacing a power package is not too complicated. The transom assembly has six bolts and three hoses. The very important thing is to line up the engine. For that you need to get the alignment tool. The rest is pretty straightforward. Let me know if you need any parts or supplies.