Can you identify this i/o engine and drive? 1979 SRV240 Flybridge

Raphness

Raphness

New Member
Jul 30, 2020
5
Boat Info
SRV 240 FLYBRIDGE
Engines
350 Mercruiser (Chevy?)/Alpha Stern Drive
Just bought this SRV 240 last week. Trying to get some new parts for it but I'm having a tough time identifying the exact make and model of the engine and drive to get the right parts.

Here are some pics:
Screen Shot 2020-07-30 at 11.03.40 AM.png
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Screen Shot 2020-07-30 at 11.02.08 AM.png
Screen Shot 2020-07-30 at 11.01.52 AM.png
 
It's a Mercruiser Alpha stern drive. The engine looks like a Mercruiser with a lot of aftermarket parts. The clear plastic fuel filter right before the carburetor needs to be replaced with a metal fuel filter. Plastic fuel filters are not legal with inboard engines.
 
Chip S said:
It's a Mercruiser Alpha stern drive. The engine looks like a Mercruiser with a lot of aftermarket parts. The clear plastic fuel filter right before the carburetor needs to be replaced with a metal fuel filter. Plastic fuel filters are not legal with inboard engines.
Click to expand...

Good tip on the fuel filter.

Someone else was saying the stern drive is actually a TRS, which maybe an older model of the Alpha. Here's the service manual I dug up:https://www.slideshare.net/jkmmemdd...r-and-trs-1979-service-repair-manual-80794687
 
I don’t believe it is a TRS. I also don’t think it’s an Alpha as they didn’t come out until around 1983 and yes, it could have been upgraded. Looks to me like an “M” or “MR”. Under that red Mercruiser label there should be a serial number. Also the trim cylinders look to be the older type seen on pre-Alpha drives.

The motor is a small block GM and knowing how heavy those old fly bridge boats were a would be stunned if it was not a 350/260hp but it has a very wonky looking closed cooling system installed.
 
The block is pre 1987, you can get more info on it from the casting number on upper port side on the back of it. Delete the plastic fuel filter, you already have the large spin-on one.
 
NorCal Boater said:
I don’t believe it is a TRS. I also don’t think it’s an Alpha as they didn’t come out until around 1983 and yes, it could have been upgraded. Looks to me like an “M” or “MR”. Under that red Mercruiser label there should be a serial number. Also the trim cylinders look to be the older type seen on pre-Alpha drives.

The motor is a small block GM and knowing how heavy those old fly bridge boats were a would be stunned if it was not a 350/260hp but it has a very wonky looking closed cooling system installed.
Click to expand...


The cooling system might look weird BC it's connected to a hose right now? But the guy I bought it from said it is unique in that it does not run through the engine, so it can circulate seawater/freshwater... Not sure I fully understand but it sounds good.

SN reads 5236734 on the sterndrive power trim and under the SN on the carburator 5242528. Nothing legible under the red label.
 
scoflaw said:
The block is pre 1987, you can get more info on it from the casting number on upper port side on the back of it. Delete the plastic fuel filter, you already have the large spin-on one.
Click to expand...

Found the casting number... GM 3970010
 
Raphness said:
The cooling system might look weird BC it's connected to a hose right now? But the guy I bought it from said it is unique in that it does not run through the engine, so it can circulate seawater/freshwater... Not sure I fully understand but it sounds good.

SN reads 5236734 on the sterndrive power trim and under the SN on the carburator 5242528. Nothing legible under the red label.
Click to expand...
No, the cooling system looks wonky because it is wonky. It looks homemade. It has a Volvo-type water pump on the front of the motor along with some seriously scary-looking plumbing. It's got nothing to do with a hose being hooked up. I've installed several closed cooling systems on SB GM motors and I have never seen anything like this.

A closed cooling system is supposed to be just that....closed from raw water, like the ocean or lake or whatever you're running in. You fill the engine, through the heat exchanger (that big, long tube in the front) with coolant and water, like your car. It is recirculated through the engine by the water pump on the front of the motor....again, like your car. The difference is your boat has no radiator like a car. The coolant/water solution is pumped through the heat exchanger.

Raw water (whatever your boat is running in) is sucked up by a different pump, called the raw water pump, through the heat exchanger and out with the exhaust. The raw water passing through the heat exchanger acts like the air through a radiator keeping the engine coolant, well....cool.

If it were me, I would take all of that crap off the engine and get back to basics. From your pictures I would say you're in Southern California. If you are planning to sun in the ocean you could look for a real closed cooling system made especially for your motor.

Best of luck.
 
TRS drives were high performance drives popular in race boats of the era and often run with an inboard style transmission in the ER. Not likely to be what you have there.

Interesting “engineering” regarding that cooling system though.
 
That motor could be worth a good deal to make someones 69 Z28 correct. GM didn't make those motors for long.
 
Raphness said:
Good tip on the fuel filter.

Someone else was saying the stern drive is actually a TRS, which maybe an older model of the Alpha. Here's the service manual I dug up:https://www.slideshare.net/jkmmemdd...r-and-trs-1979-service-repair-manual-80794687
Click to expand...
TRS outdrives are the sport model of the TR. The TR does not have a water pump so does not have the water pick up holes shown in this photo. The engine cooling water comes in thru a sea cock in the hull. This is why I don't think your drive is a TRS. My boat has a belt driven water pump that feeds an engine mounted circulation pump. You have a closed cooling system so I do not know the plumbing layout after the sea cock.

The TR and TRS both have in-board transmissions, a dead give away as to is it a TR or a TRS.

VR
hpcrank
 
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