When to pack it in on a project boat.

[GSX455]

So, I've been working on an oxymoron, a "free" boat. someone gave me a 1981 Renken with a Mercruiser 120 boat, and I took it home thinking I could rebuild it, for not too much money. The motor would not turn over and I took off the stern-drive, and then it turns over. It worked on the motor, rebuilt the carb, new ignition coil, wires, etc.
So, while I was getting it running, I put a garden hose on the water pump intake, and water poured out of a freeze plug, that was hidden from view, see photo.
The compression is about 90-100 psi in 3 cylinders, except for #2 which was about 60 psi.
Is it worth at this point? I could sell the rebuilt stern drive and junk the boat at a landfill.

I do not have the $5000 for a decent boat, but $2000 for a rebuilt motor I can put in where I already spent $1000 on the stern drive.

Thanks for any advice, anytime I mention the word boat at a store, I loose money.

GSX455

 

[Bt Doctur]

A missing core pug is a sign the motor has/had freeze damage.

 

[Rick Stephens]

I would say you need to pop a core plug in, cap the exhaust manifold at the elbow and pressure test by pressurizing at the water in line to the thermostat. (15 psi) Determine where that motor is before making any choices. Total cost to do that will be a few dollars. Well spent at this point.

 

[JackBronson]

Agree with Rick that you can do a little more work to get a much better idea of the motor situation. However, take a good look at the boat overall in deciding to go from there. How is the floor? How is the vinyl? Of course, if those don't really matter to you, then you can really just focus on the power package...

I had a very nice Starcraft bowrider with great vinyl and a solid Merc 5.0. However, she was 30 years old and the wooden floor and substructure was on the way out. I did not want to spend my boating time trying to fix all that, so I sold it. Look at the threads on this site from guys who got involved in project boats - they convinced me of my limitations.

 

[GSX455]

Thanks, I'll go get a core plug and press it in. The boat is about 30 years old, and the floor is in decent shape, it just need new carpet and upholstery

 

[Grub54891]

I picked up a 1985 Larson, 140. All core plugs blown out. Installed the plugs, cleaned it up, and ran it hard for the first season. No issues. Sometimes ya get lucky. What happens sometimes is it will freeze enough to pop them out, then warm up and all the water drains out. I think I was extremely lucky, so now my spare motor just sits waiting for my next project.

 

[Bondo]

Sometimes ya get lucky. What happens sometimes is it will freeze enough to pop them out, then warm up and all the water drains out. I think I was extremely lucky, so now my spare motor just sits waiting for my next project.

Ayuh,..... Exactly,...... How cold,.... For how long,......

 

[GSX455]

New leak location, once the freeze plug was sealed, the it started leaking around the bellhousing near the starter.
It there a bellhousing seal.

This looks like I pull the motor and fix the leak around the bellhousing.

Thanks for any suggestions.

 

[Walt T]

I don't remember on this specific engine but there may be a freeze plug back of block. Yes remove engine and flywheel to see. But first check hoses above and around engine to make sure it not just appearing to come from the engine. The hose that attaches to the transom is back there cant hurt to check. Keep an eye on the motor oil, if it gets all milky white then the engine is junk.

 

[Grub54891]

Yes there is a core plug under the flywheel.

 

[GSX455]

Is there an easy way to replace that freeze plug? That freeze plug, which you can't see, and in Mercury Motor's infinite wisdom put some place you can't access without pulling the motor out of the boat?
Can the bellhousing be removed, or is it somehow attached to the motor mounts?

I did check the motor oil after I ran the boat, and the oil was clear.

 

[Grub54891]

You have to pull the motor. There is no other way. With a proper gantry, or lifting devise, it takes less than 1/2 hour to unbolt it.
I had mine out and back in within 3 hours, replacing every core plug.
Unbolt rear mounts, front mount, remove drive, unplug wiring harness,ground wire, shift,throttle cables,fuel lines. Lift out.

 

[GSX455]

Thanks for your help, luckily I have an engine hoist.

 

[Rick Stephens]

Is there an easy way to replace that freeze plug? That freeze plug, which you can't see, and in Mercury Motor's infinite wisdom put some place you can't access without pulling the motor out of the boat?
Can the bellhousing be removed, or is it somehow attached to the motor mounts?

I did check the motor oil after I ran the boat, and the oil was clear.

Mercruiser doesn't have any wisdom involved in the design of a GM motor. Keep in mind that those plugs are not designed in any way to be 'freeze' plugs. It is only coincidental that they pop out when a motor is frozen. Their actual purpose is to hold and then remove the inner sand during the casting process. Gm builds in core plugs at the rear of any motor with water jackets extending around the rear of rearmost cylinders. Pretty much every motor.

 

[matt167]

Yup. People forget that the Merc 2.5 and 3.0l 4cyl was the old Nova 4cyl which was actually only used in the Nova for a few years. It was just what worked off the shelf in a marine situation, and worked well. The 3.0L variation Mercruiser DID increase the displacement on but it is just a Chevy engine..

Free boat is never free. The little 4cyl was used by OMC and Mercruiser. If you needed another, they don't cost a ton. Make sure the hull is sound first. Core sample transom and stringers ect...

 

[GSX455]

Thanks for all of the information, I now recognize the old Iron Duke 2.5 liter 4 cylinder, made for boats. Once I pulled the the engine to get to the freeze plugs, I noticed the coupler from the flywheel to the drive splines was out of alignment.
Is this alignment something I can fix with a metal pipe while installing a the out-drive, or should I buy a new coupler?
Thanks again.

 

[Maclin]

That coupler looks like it has spun the spline hub in the rubber, you need a new one in my opinion.

As far as fixing the alignment, the wording is usually "set" the alignment. You need the proper alignment procedure and tool(s), not just a pipe. Some new mounting related parts may be needed.

Another point of order, engine is not the Iron Duke, that was a Pontiac engine, not the same.