New guy with lots of questions!!

[Greenacarina]

Hi everyone!
Brand new boat owner here with a not-so-new boat that i am trying to revive.
I am a long time car guy, so mechanical things and engines are familiar territory.
I have a 17 ft tri hull with a mercruiser 221hp inboard. I have been told it's a ford 302 but my little bit of internet research says maybe ford 351? I am not a "ford guy" so this, too, is somewhat new territory.
Here are the clues to this mystery so far.....
Engine froze and popped out 2 feeeze plugs. Couldn't see any cracks in the block.
Lower thermostat housing is cracked and appears someone tried to jb weld it...unsuccessfully.
Oil looks good and clean...not "new" but close.
Today i hooked up a battery, pulled the spark plugs and did a compression test.
Everything read about 95 psi...which isn't good...but is also very weirdly consistent...so i bought a new compression gauge just in case.
Here are my first few questions -
Do i have options (better or worse) for my thermostat housing?? I saw one used on ebay for $45

If this engine is "toast"...am i better off rebuilding it, or putting something newer and more modern in there?

Any upgrades for reliability i should consider?

I'm sure i've left some info out...but i am here to learn and put together a reliable boat.

Thanks in advance!
Chris

 

[Bt Doctur]

Ford has not been in the marine world for a long time so engine parts are rare. Find a donor boat and go with a later GM motor

 

[wellcraft-classic210]

I am not a Ford experts but have a few thoughts:

It sounds like the water in the block froze given the freeze plugs and cracked t-stat housing // Their could be other cracks as well in the block, heads , exhaust manifolds etc. Some engines keep developing new leaks from stress cracks after such an event while others have minimal damage--

Before spending any $ on parts -- you may want to try sealing it off and pressure testing the cooling passages. It should hold 10 psi easily without leaking down quickly.

Otherwise any problems may reveal themselves more slowly.

( Others who have done this may have added input if you want more details on the procedure )

I think your compression may be acceptable if the engines been out of use for a while. The fact that the cylinders are all about the same pressure is a good sign. -- it seems that's enough compression to at least start it and see how it runs.


The GM option sounds like very good advice if the current motor is costly to repair.


I went through the same learning curve on boats from cars-

-1 tip :

I would suggest you learn the details of the required outdrive preventive and regular maintenance if you have not done so -- Bellows , Impellers, pressure testing etc. Save lots of headaches and $

 

[tpenfield]

Put some butter and jam on that motor, because it is probably toast. GM would be the way to go, as per the previous comments. Maybe you can find a full Mercruiser donor engine & outdrive.

You will have to post some pictures of the boat, etc. We like pictures

 

[Greenacarina]

I am not a Ford experts but have a few thoughts:

It sounds like the water in the block froze given the freeze plugs and cracked t-stat housing // Their could be other cracks as well in the block, heads , exhaust manifolds etc. Some engines keep developing new leaks from stress cracks after such an event while others have minimal damage--

Before spending any $ on parts -- you may want to try sealing it off and pressure testing the cooling passages. It should hold 10 psi easily without leaking down quickly.

Otherwise any problems may reveal themselves more slowly.

( Others who have done this may have added input if you want more details on the procedure )

I think your compression may be acceptable if the engines been out of use for a while. The fact that the cylinders are all about the same pressure is a good sign. -- it seems that's enough compression to at least start it and see how it runs.


The GM option sounds like very good advice if the current motor is costly to repair.


I went through the same learning curve on boats from cars-

-1 tip :

I would suggest you learn the details of the required outdrive preventive and regular maintenance if you have not done so -- Bellows , Impellers, pressure testing etc. Save lots of headaches and $

Yes!! Exactly where my head was at. Want to make sure this engine is viable before putting any dough in it.
Where can i find outdrive service info?? I know nothing about them.

Thanks!

 

[interalian]

Yes!! Exactly where my head was at. Want to make sure this engine is viable before putting any dough in it.
Where can i find outdrive service info?? I know nothing about them.

Thanks!

Look in the "ADULTS ONLY" sticky up at the top of the page.

 

[harleyman1975]

When you did compression test was it at least 4-5 revolutions with a wide open throttle? all plugs pulled? 221 is more than a 302 only 188 hp there. sierra still makes parts for the fords if you are determined to try to get this one back up and running. I have a set of good manifolds, intake, thermostat housing and various other parts I would be willing to part with at a reasonable price if you need them.

 

[achris]

Merc stopped using Fords in 1977. So the absolute youngest that engine can be is 40 years. In 1983 Merc changed the gimbal housing and inner transom plate, so continuing to use that restricts you to anything 35 years or older. Merc changed the gimbal housing again in 1992.

Core plugs popped out and the thermostat housing cracked. If the block isn't cracked, it will be some sort of miracle.

Best option. Find a donor boat with a GM V6 or V8 from this century and swap the whole lot over.

Chris. ...

 

[Greenacarina]

Merc stopped using Fords in 1977. So the absolute youngest that engine can be is 40 years. In 1983 Merc changed the gimbal housing and inner transom plate, so continuing to use that restricts you to anything 35 years or older. Merc changed the gimbal housing again in 1992.

Core plugs popped out and the thermostat housing cracked. If the block isn't cracked, it will be some sort of miracle.

Best option. Find a donor boat with a GM V6 or V8 from this century and swap the whole lot over.

Chris. ...

I agree that this engine is probably toast. But...just for clarity's sake...i think that t-stat housing was cracked before the freeze plugs popped out since someone had epoxied it and that failed.
So far you guys have been an amazing wealth of knowledge and the adults only section is a huge help!
I plan on testing everything i can test to make sure i know what failed with this engine (if anything) and to ensure a reliable boat once i get it on the water.
The last time it was tabbed was 2010 and i notice the gas gauge reads about 5/8 full...so i will be draining a lot of crappy gas soon.
Should have some time tomorrow to work on it again

Thanks everyone!
Chris

 

[Greenacarina]

...and i am keeping an eye open for a modern GM setup too

 

[wellcraft-classic210]

Good luck -- Keep us posted on your progress --!

 

[Greenacarina]

Intake manifold question

So, as i learn more about my new boat and investigate it's 40 years of battle scars and neglect...i now see the JB weld repair that has failed is not on the thermostat housing but on the intake manifold.
I believe it's a mercruiser 888. I am wondering what makes the marine manifold different than the automotive manifold?
The manifold i have appears to be cast iron...i know they can be tricky to weld, but would it be worthwhile to have it done?

Thanks
Chris

 

[Fishingaddict88]

I don't know about worthwhile but I don't see how it could hurt. Sounds like you already know a little bit about cast iron, but usually It tends to crack if you weld it cold. Preheating it works and letting it cool slowly

Main thing I could see is as long as it's not where a gasket would be going, should be fine. Then again I'm no expert..

 

[tpenfield]

The engines are pretty much like the truck versions of the automotive engine. Not much difference. Head gaskets are stainless steel, the core plugs are brass, the cam is a bit mild with less valve overlap than you might see in an automotive application.

Mercruiser, and the other boat engine companies buy the base engine from the automotive companies, (mostly GM now) and put marine versions of fuel, ignition, cooling, and exhaust systems.

So the intake manifold is probably the exact same as the automotive version for that engine.

As stated in you other thread, the engine sure sound like it is beyond repair due to freeze damage. Think about all the cracks that you cannot see.

 

[Scott Danforth]

from an intake perspective, cast-iron marine intake is exactly the same as cast iron truck. However if looking at aluminum. Marine aluminum manifolds have naval brass cast as the first alloy and aluminum cast as the second alloy. that way water only comes in contact with the naval brass.

if a motor is freeze damaged, replace it. the structural integrity of the motor has been comprimized

 

[Greenacarina]

The engines are pretty much like the truck versions of the automotive engine. Not much difference. Head gaskets are stainless steel, the core plugs are brass, the cam is a bit mild with less valve overlap than you might see in an automotive application.

Mercruiser, and the other boat engine companies buy the base engine from the automotive companies, (mostly GM now) and put marine versions of fuel, ignition, cooling, and exhaust systems.

So the intake manifold is probably the exact same as the automotive version for that engine.

As stated in you other thread, the engine sure sound like it is beyond repair due to freeze damage. Think about all the cracks that you cannot see.

Yep that is my next step. I have a total of 4 core plugs missing. Gonna get some new plugs to fill those holes and pressure test the system. I'm sure i can plug that crack in my manifold enough to do some testing.
Will see what happens!

 

[Scott Danforth]

No Title

I wouldn't spend too much time working on the busted motor