Motor Swap

[bigcatlittledog]

Good morning I am new to the forum and am seeking advice on a technical matter.

I have a 135hp Chrysler outboard which has damage to the exhaust plate/housing between water jacket, also the bolts were rusted in so I have deemed the block useless. see attached

I have access to a 120hp motor in another state of Australia (pic attached) with a clagged gearbox and electrics.

My question is can I bolt the entire 120hp motor straight on to the 135hp housing and replace the electrics from the 135?
From the pics the motors seem different but how different is the question.

Thanks for any advice

 

[Justinde]

Re: Motor Swap

If you get the year model of both that would help, but I suggest that the 135hp gearbox and electrics might be easier to put on the 120? Anyhow, if you can get the year models of both motors, you can look on this site at the different part numbers of the respective units, and also check the gear ratio's.

I know it didnt help much yet, but get back to us

 

[bigcatlittledog]

Re: Motor Swap

Thanks very much for your quick response. Both are from 1976. I am probably wrong but I would think it expensive to change casts and I believe this model only ran in 76 and 77? I would guess they would be the same?

As the 135 is on the boat already Im hoping just to unbolt the block and bolt on the 120 but am obviously unaware if the bolt patter is the same.

Im told the problem with the 120's electrics is the Power Pack. Is this the black square box? I assume this is a coil and shold be the same, economy of scale etc...but again I'm no expert.

So the intention is to change the block with everything on it from the 120 and swap the Power Pack from the 135.

From the pics the water jacket (where spark plugs are) appears different? so there goes my theory about cost savings!

On the 135, beneith the water jacket was a small cover (held by 2 nuts) with dome (in which the housing cracked.) Inside was a spring (and pieces of crumbled aluminium cast). Is this part of a valve for the cooloing? I am contimplating oxy/aluminium welding but have no experience in this area (electrical engineer). I would guess block swap would be easier and more reliable?

Sorry for the disjointed message, but thats how I think

 

[roverfj1200]

Re: Motor Swap

I have a 135hp leg running a 120hp powerhead at the moment everything will swing over OK. I have been watching that motor on Ebay too. There are I think 3 differant ignition systems on that era of moter but all can be swapped from one engine to the other. The only differance in the 100 + hp blocks was the bore and stroke of the 135? but all bolt patterns are the same.

Cheers

 

[Frank Acampora]

Re: Motor Swap

Both engines can not be 1976! Force only started branding the name in 1984. Original Force engines were white and later ones were dark: blue or black. Late Chrysler engines after 1978 and force engines used a Prestolite ignition while your 135 has the distributor Motorola.

The Force 120 will bolt right up to your leg. If it does not have carbs, the 135 carbs will fit. If the Force manifold has small carb holes, simply replace with the 135 manifolds. Everything is the same.

However, the ignition system will not swap unless you do some modifications. If you have access to a lathe, they will be easy. If your 135 block is salvagable at all, it might just be a better option to repair it. The valve at the bottom that you describe is a water bypass. when there is high pressure in the water jacket, it is forced open and diverts water directly back into the leg. Late Chrysler and early Force engines did away with them, so you can plug it with no harm.

Back to the Force block: Your Chrysler is the older two piece lower unit. It will not bolt up to the Force leg and is not a particularly well designed unit. The Force lower unit has a larger water pump AND, the Force lower unit is actually about 3 MPH faster. Because the Chrysler is rated at the crankshaft and the Force at the prop, the Force 120 probably delivers the same horsepower to the prop as the 135. So, if you could find another lower unit for the Force, it would be better to repair that engine.

Back to the ignition: To use the ignition from the 135 on the Force block, you must first tap the distributor mounting holes on the block to 3/8 X 16. Then you must take the alternator stator mount and turn down (on the lathe) the plug portion that fits into the block because the top of the Force block is lower. If you can find a retrofit top from an old Magna-power II converted engine it will bolt right on, but they are rare and expensive (80 bucks US). You must then either redrill the mount for the five 1/4 inch mounting screws drill and tal the block for the four 3/8 X 16 original mounting screws. After that everything bolts-up and the 135 flywheel, which you must use, will mount on the Force crank.

EDIT: How did I get that the second engine was a FORCE? Jeeze! I really must be getting senile!

If both engines are Chrysler, and if both are the same year, then everything will swap. period. You may need to swap manifolds because some 120 engines used a smaller WB carb, but that's it.

 

[carholme]

Re: Motor Swap

dog;

There are several models for the 120 and 135 but all of them seem to break down into two different parts listings:

http://www.crowleymarine.com/mercury-outboard/1740.cfm

http://www.crowleymarine.com/mercury-outboard/1744.cfm

Below is a list of the models 120/135, 1976

1208BD 120 1976
1208BE 120 1976
1208BF 120 1976
1208HD 120 1976
1208HE 120 1976
1208HF 120 1976
1209BD 120 1976
1209BE 120 1976
1209BF 120 1976
1209HD 120 1976
1209HE 120 1976
1209HF 120 1976

1358BD 135 1976
1358BE 135 1976
1358BF 135 1976
1358HD 135 1976
1358HE 135 1976
1358HF 135 1976
1359BD 135 1976
1359BE 135 1976
1359BF 135 1976
1359HD 135 1976
1359HE 135 1976
1359HF 135 1976


For 120 or 135 models:

8BF/8HF/9BF/9HF use the .1744 parts link above

For all other 120 or 135 models, use the .1740 parts link above.

Hope this is not too confusing and if you do not know your model number, there are still only two parts listings for all of the models and you may be able to determine yours from those listings.

Gerry

 

[carholme]

Re: Motor Swap

Frank and rover;

My apologies for stepping on you, I didn't realize that one of the engines was a Force. Is it, or are they both Chryslers?

Gerry

 

[Frank Acampora]

Re: Motor Swap

No! That was me! I edited the reply. I just don't know what made me think one engine was a Force.

Big cat: The head on the other block is different but the same. The water jacket on one is just a cast tube running from top to bottom while the other more massive head has a complete water jacket inside of it. It has a better thermostat housing and obviously more cooling so even though it is heavier, it would be the head to use if possible. CAREFUL though. the 120 has a bore of 3.3125 (3 5/16) and smaller piston baffles. I forget the bore on the 135 but it MIGHT have been 3.375 93 3/8) with larger piston baffles. IF SO, the 135 head will fit on the 120 block but the 120 head will NOT clear the piston baffles on the 135. If both engines are 3.3125 bore that either head will fit. head gasket is the same for either bore--in fact, any four cylinder Chrysler.

The engine on the boat shows a "newer" style --around 1976-77--three bolt, two piece, lower unit while the one on the stand shows a leg for the older style two bolt, two piece lower unit. Both use the same mounting pattern and these lower units are swappable.-- even though the leg looks different.

 

[bigcatlittledog]

Re: Motor Swap

I heard virgin coconut oil is the next cure for senility...very funny reading your posts. Frank dont forget you owe me $20,000

In summary two different configurations of legs but 120 and 135 have same bolt pattern and will mate to either legs.
Electrically several types so use group from either 120 or 135.
Are the bolt patterns the same between years ie 76/77? for the 120 and 135? .....NOT FORCE, FORCE CAME OUT IN 84

Finally a warning on coconut oil. I suggested my dad use it and my mum has reported that is an afrodisiac. Maybe she was using it wrong??

Thanks everyone for your hard work.



Also sorry, is it common on these motors for the bolts to rust/weld in on these motors? or any outboard. I snapped off 3/4 of the bolts from the exhaust plate today before I took the pic.

The water channels were chock full of salt. How do you get rid of this for the next block? hot water flush? I fell in love with these motors when I saw it on you tube (Chrysler Outboard 130 running with cover on and off).

 

[Justinde]

Re: Motor Swap

Hey catdog ( one of my fave cartoons!)

I removed the exhaust plate on my 125 force with the same result- full of salt and silt. I was lucky enough to find a great condition used one on ebay for just $50.00. I snapped off just one bolt, which needed to be drilled out and re-tapped. Now that it is all new, the only thing to keep it that way is a good freshwater flush after each use. This part may not suit, but keep checking ebay

http://cgi.ebay.com.au/1982-Chrysle...at_Parts_Accessories_Gear&hash=item1e614a2ee1

Cheers

 

[bigcatlittledog]

Re: Motor Swap

Hey catdog ( one of my fave cartoons!)

I removed the exhaust plate on my 125 force with the same result- full of salt and silt. I was lucky enough to find a great condition used one on ebay for just $50.00. I snapped off just one bolt, which needed to be drilled out and re-tapped. Now that it is all new, the only thing to keep it that way is a good freshwater flush after each use. This part may not suit, but keep checking ebay

http://cgi.ebay.com.au/1982-Chrysle...at_Parts_Accessories_Gear&hash=item1e614a2ee1

Cheers

Very impressive. Thanks for the ebay tip