Force/Mercury Frankenstein

[The Force power]

okay I went out and bought two parts-motors;
- 89 Force with prestolite- ignition with the "dog bone" style Re-circulation and old style fuel-pump
-92 Force with Mercury ignition system BUT also has the "old style" fuel-pump & dog bone re-Circ.

I all ready have also a 90 that has a square fuel-pump, without the dog bone Re-circulation and prestolite-ignition.

How many versions are out there? is at least most or all parts inter changeable lol

 

[Nordin]

When Mercury started to put their parts to the Force engines there was a couple of combinations.

 

[jerryjerry05]

The motors went through a lot of changes(3-5000) over the years.
Most were little changes like a screw or a nut, little things.
One of the biggest changes was the size of the standard piston.
This might be the difference between the 89 and 92 blocks you have???
Then they changed the exhaust cover, looks almost identical until you try to use the gaskets from
an early 80's to a late 80's , they don't match.

They changed the lowers in 89 from a 1 piece drive shaft to the 2 piece used in the L-Drive
They also went to a standard gear ratio on all the drives in 88-89.

In 87 they went to the blue/black paint and new covers.

For specific changes??? look up the parts comparing the years and model#s

 

[The Force power]

Thanks guys

 

[The Force power]

The motors went through a lot of changes(3-5000) over the years.
Most were little changes like a screw or a nut, little things.
One of the biggest changes was the size of the standard piston.
This might be the difference between the 89 and 92 blocks you have??

okay, all right I am up for a challenge here, thanks for the input

 

[The Force power]

Well, now I have 4 Force engines & all of them have low compression on one of their Cylinders.
I should have enough ingredients to make one working motor.

When every thing is "back together" should I put on the Merc. ignition-system or the Prestolite ? (providing it works)

 

[The Force power]

The motors went through a lot of changes(3-5000) over the years.
Most were little changes like a screw or a nut, little things.
One of the biggest changes was the size of the standard piston.
This might be the difference between the 89 and 92 blocks you have???

For specific changes??? look up the parts comparing the years and model#s

I Did, boy you were not kidding about the changes with the Pistons!!

 

[jerryjerry05]

The Mercury vs Prestolite.
The trigger base will decide which system you use.
Most of the "parts" will swap but the ignition might give you trouble if trying to
use the newer system on the older block.

 

[jerryjerry05]

Another thing.
The exhaust chest cover and gaskets changed in the 87-90 years.
Double check the holes for alignment.

I found out the hard way

Also if you decide to remove the cover??
It a real PITA to make it seal again.
Time/heat makes the edges rounded and the gaskets don't fit right.
You can get the surfaces milled smooth and then it won't be so hard to replace.

The gaskets, come in different thicknesses.
Make sure the ones you use are the OEM thick ones.

 

[The Force power]

The Mercury vs Prestolite.
The trigger base will decide which system you use.
Most of the "parts" will swap but the ignition might give you trouble if trying to
use the newer system on the older block.

Thanks Jerry,

I had not looked up the part# for the Trigger-base to see if there were differences, either way I have now multiple (trigger-bases) prestolite ones & one for the merc. ignition

 

[The Force power]

So far I have only opened (removed the head) on one with the prestolite-ignition & dog-bone and found the Pistons stamped with a C that means; I have three engines with three different Cylinders.
I really hope that the forth one has Cylinders I can use to Swap to make one good engine

 

[jerryjerry05]

Measure the holes????

 

[The Force power]

Measure the holes????

yes, Jerry I will do that.

I pulled the head on the forth motor ('92 force with dog bone style but with Merc.-ignition) and was relieved to see 3 identical pistons inside. upon further inspection I noticed no scoring on any of the cylinder walls (smooth as glass)

I found that odd for an engine that supposedly had low compression on one of the cylinders(I was told when bought)
to my surprise I see that the Head-gasket is blown (the ring in the gasket on #2) head is cleaner at #2 & #2 spark-plug rusty

My theory is after the gasket blew, small amounts of water were being drawn in on the down-stroke of #2 (through split in gasket)

I'm going to slap on of the other heads with a good gasket on and check the compression to see / confirm my theory

 

[jerryjerry05]

I bet your theory is right.
Bought a 125 for 200$ because they blew the motor.
Low compression on one cyl. NOT! bad gasket.

Another for 100$ the flywheel was wobbling.
The owner thought he bent the crank. NOT!! sheared the key.

 

[The Force power]

1420footer OTE=jerryjerry05;n10801779]I bet your theory is right.
Bought a 125 for 200$ because they blew the motor.
Low compression on one cyl. NOT! bad gasket.

Another for 100$ the flywheel was wobbling.
The owner thought he bent the crank. NOT!! sheared the key. [/QUOTE]

yeah, I like those purchases! when we don't get shafted for once.

I cleaned-up the cylinder walls with emeral-cloth(not sure if that spelled right) slapped the spare head on.
I can believe the torque value for head bolts 21 ft/lbs or 254 in/lbs. I found that low
( I use to rebuilt Compressors aluminum heads/body with 3/8 bolts torque value at 28 ft./lbs.)

Anyways........when it was all together the readings are #1 @ 130 #2 @ 140 #3 @ 142

I know.....I'm not happy with it either, I will RE-torque & check again
I was pleasantly surprised the Starter & Ignition part is working, although I will convert this back to a Prestolite ignition.

 

[The Force power]

1420footer OTE=jerryjerry05;n10801779]I bet your theory is right.
Bought a 125 for 200$ because they blew the motor.
Low compression on one cyl. NOT! bad gasket.

Another for 100$ the flywheel was wobbling.
The owner thought he bent the crank. NOT!! sheared the key.

yeah, I like those purchases! when we don't get shafted for once.

I cleaned-up the cylinder walls with emeral-cloth(not sure if that spelled right) slapped the spare head on.
I can't believe the torque value for head bolts 21 ft/lbs or 254 in/lbs. I found that low
( I use to rebuilt Compressors aluminum heads/body with 3/8 bolts torque value at 28 ft./lbs.)

Anyways........when it was all together the readings are #1 @ 130 #2 @ 140 #3 @ 142

I know.....I'm not happy with it either, I will RE-torque & check again
I was pleasantly surprised the Starter & Ignition part is working, although I will convert this back to a Prestolite ignition. [/QUOTE]

 

[Firefighterfox]

I bet your theory is right.
Bought a 125 for 200$ because they blew the motor.
Low compression on one cyl. NOT! bad gasket.

Another for 100$ the flywheel was wobbling.
The owner thought he bent the crank. NOT!! sheared the key.

I don't know where to start this question about a Force linkage issue. But you seem to be the one to ask. "Firefighterfox"

 

[Nordin]

May the Force be with you...... those numbers for the compression are not so bad at all.
Under 10% in differrence, yes it will not perform as "new" but I think it will run decent.

As I understand you only cleaned up the cylinder walls.
Maybe you can get the compression to increase by hone the cylinders.
Is there some score in the one with lowest compression?

I have done this on a 70Hp 1970 Chrysler, was some score in number 3 cylinder and the piston/rings was bad too.
The numbers of the compression was #1 125, #2 130 #3 110.

I pull the piston out with the power head still in place (disassemble the connecting rod through the intake manifold), hone the cylinder and put a used good piston with used rings in and reassembled.

The compression rise to 120 at #3 and it is running pretty decent.
Yes I know this is a low cost restoring, but is working and I maybe will do a restoring the right way later with bore and new pistons and rings.

I have in mind that it is a 49 years old engine and a restoring the right way will cost about 5-600 dollars if bore all three change all pistons.
A lot of money !!!

 

[jerryjerry05]

The low comp #s could be the gauge or the way it was taken?
They don't seem that bad.

Once you get it running and have time.
Do a decarb and see if the #s come up?
\
Did you replace the rings or use the old?

Once you run for a while? the #s might come up?

 

[The Force power]

I don't know where to start this question about a Force linkage issue. But you seem to be the one to ask. "Firefighterfox"

Welcome to Iboats Firefighterfox,

To ask you question in the right place;

It's helpful to read the yellow sticky notes on the top of the page first and/or you can type key words of your question in the search bar under advice (you'll find a lot of useful information that has been given in the past to people that asked the same question).
I you can't find what you're looking for, then to ask a question by clicking on "new post"