Motor displacement

[SweeperForce]

Just for common knowledge does anyone know the cubic inch or liters of an '89 150 horse? I searched the web for hours and up with nada. So I'd thouht I'd ask the professionals.

Thanks,
Tom

 

[Frank Acampora]

Re: Motor displacement

That one should be 3.3125 bore by 2.80 stroke. SO: The formula is cubic inces of a cylinder 1.2 diameter squared x 3.1416x 2.80 x 5


3.3125 divided in half is 1.656
squared (times itself) is 2.742
times pi (3.1416) is 8.614 (square inches of the cylinder diameter)
times 2.80 (stroke) is 24.11 cubic inches per cylinder
times 5 is 120.599 total cubic inch displacement of engine.


Two cycle engines have approximately 1/3 of the displacement as ports so it is ineffective. THUS total EFFECTIVE displacement is about 80.4 cubic inches.

If your 89 has the 3.375 inch bore simply plug it into the formula instead of 3.3125.

oops--had to edit, got pi wrong.

 

[SweeperForce]

Re: Motor displacement

Wow. Thanks for the fast reply. There is a good amount of math involved here. If one were to determine the cylinder bore how would he find out, other than removing the head and measure. Thanks again Frank.

Tom

 

[Frank Acampora]

Re: Motor displacement

Go to any site selling pistons and look at which bore size is standard for your year 150. I don't have my Wiseco catalog handy but I am reasonably certain that the first two years of production had 3.3125 bore while later ones were 3.375.

Even with a 3.375 bore, it only adds 4.75 cubic inches for a total of 125.25 cubic inch displacement. Why is it critical to know this?

EDIT: if your engine has the small venturi WB carbs, then it is a small bore. If it has the massive TC carbs, then it is a 3.375.

BTW: About 60 cubic inches equals one liter (litre for our British Empire friends)) displacement so the 150 will be just over 2 liters displacement.

 

[SweeperForce]

Re: Motor displacement

I'm repainting my whole motor white. Cowl, leg, lower unit, everything. I found some pretty cool graphic designs for the cowl on the web. Plus there is a local shop here that does custom work. I addition to the horsepower, I aslo want to put on the liters.
I guess after seeing your artwork, it inspired to find a radical new design for my 23 year old boat.

Tom

 

[jerryjerry05]

Re: Motor displacement

Manual says.
Displacement: Prior to 1990 B Model 124.0 cu.in. (2032cc) After 1990B 128.6 cu.in. (2108cc).
Timing 32 btdc at 5000rpm.
Firing order 1 5 2 3 4

 

[Frank Acampora]

Re: Motor displacement

Ah--HA! That means that the crankshaft stroke is about 2.875, like the old Chrysler 140 four cylinder and Force 125, not 2.80 like the 120. ---An assumption I had to make for the formula. Anyway, 4 cubic inches doesn't make any difference for this purpose.