How to set up Mercruiser 7.4L for Bench Testing after rebuild ???

[tpenfield]

I am nearing the completion of a valve job and refurb. on my 1991 Mercruiser 7.4L. I removed the engine to do all this and now it sits in my garage - soon to be ready.

I plan on running the engine *before* I put it back in the boat to check things out. In looking at the wiring diagram for the engine, it looks like I need to hook up the basics for ignition power and starter activation, plus fuel, water, etc.

I have searched the forums quite a bit and it looks like some folks have done this before, but I have not found any specific threads on how to set it all up.

Thanks for any advice on how to set up the engine in a "bench test" mode.

1991 Mercruiser 7.4L 330hp. S/N 0D460420

 

[90stingray]

Re: How to set up Mercruiser 7.4L for Bench Testing after rebuild ???

I am nearing the completion of a valve job and refurb. on my 1991 Mercruiser 7.4L. I removed the engine to do all this and now it sits in my garage - soon to be ready.

I plan on running the engine *before* I put it back in the boat to check things out. In looking at the wiring diagram for the engine, it looks like I need to hook up the basics for ignition power and starter activation, plus fuel, water, etc.
I have searched the forums quite a bit and it looks like some folks have done this before, but I have not found any specific threads on how to set it all up.

Thanks for any advice on how to set up the engine in a "bench test" mode.

1991 Mercruiser 7.4L 330hp. S/N 0D460420

It looks like you have already answered your own question... (see bold in quote) Hook up everything that is required so it will start... if you plan on running it awhile, use water for coolant. I have done this on a 350 for a 78 webbcraft. Broke in a cam and adjusted the valves, changed the oil, then installed the engine. Do you have a stand to run it? Sometimes an engine stand has clearance issues to start 'em up, if i remember right. I have seen people run engines hanging from a cherry picker Goodluck!

 

[mxcobra]

Re: How to set up Mercruiser 7.4L for Bench Testing after rebuild ???

put mine on a pallet, used some wood blocks just like engine mounts in the boat.
dont forget the ground wires

 

[achris]

Re: How to set up Mercruiser 7.4L for Bench Testing after rebuild ???

I built my own stand, on casters. Works great....

 

[tpenfield]

Re: How to set up Mercruiser 7.4L for Bench Testing after rebuild ???

Thank you for the replies . . . looks like the set up should be fairly simple.

The engine is sitting on cinder blocks, but I was planning on putting some dollies underneath them to move the engine out of the garage into open air.

Here is the engine nearing completion. I'm just waiting for some electrical components that I ordered online. I did a valve job, replaced the timing chain and cleared the block of several pounds of iron sediment. Also replaced exhaust manifolds and elbows. I did a lot of rust treatment and re-painting

It is all documented on my web page: http://www.tpenfield.com/Formula242/Top-end_Rebuild.html

 

[04fxdwgi]

Re: How to set up Mercruiser 7.4L for Bench Testing after rebuild ???

Thank you for the replies . . . looks like the set up should be fairly simple.

The engine is sitting on cinder blocks, but I was planning on putting some dollies underneath them to move the engine out of the garage into open air.

Here is the engine nearing completion. I'm just waiting for some electrical components that I ordered online. I did a valve job, replaced the timing chain and cleared the block of several pounds of iron sediment. Also replaced exhaust manifolds and elbows. I did a lot of rust treatment and re-painting

It is all documented on my web page: http://home.comcast.net/~tpenfield/Web_Page/My_Power_Boat/Top-end_Rebuild.html


View attachment 123745

I would build a solid "stand", be it steel or 4x4's, tying everything together into a solid frame, like on a pallet or something. Got a feeling she'll "walk off" those cinder blocks with a little vibartion and fall over to the ground. Hmmm, a running Big Block Chevy laying on it's side doesn't sound like something I would want to be around. Everything else is pretty straight forward. Power to ignition (with a switch to turn it off), power to starter, fuel and cooling water and away she goes. I would also use a couple of pieces of 4" plastic pipe to direct the exhaust / water out away from the flywheel area. Keep an extinguisher handy too, just incase.

I think I would also spring for some cheap mechanical or electric guages for volts, oil pressure and water temp (and maybe a tachometer) while she's running. Would suk if something wasn't right and you weren't aware of it during the "floor run".

PS: Video it and put it up here so all can enjoy the sweet sounds of the BBC with shortie exhaust.

 

[tpenfield]

Re: How to set up Mercruiser 7.4L for Bench Testing after rebuild ???

Engine assembly is done . . . Getting ready to fire it up . . . maybe today if I can get some dollies to wheel it out of the garage.




I figured that I would hook up a 12 light to the oil pressure alarm sensor just to know if there is an oil pressure problem while it is running.

 

[tpenfield]

Re: How to set up Mercruiser 7.4L for Bench Testing after rebuild ???

PS: Video it and put it up here so all can enjoy the sweet sounds of the BBC with shortie exhaust.

Here ya go . . . I fired it up today and ran it for about 10 minutes. . . it sounded OK.