Single vs dual exhaust props

[SweeperForce]

My freind got rid of his Force and got an Evinrude. He had 3 propeller hubbed to his Force (2 aluminum and 1 stainless steel) He asked if I wanted them for free. Well I could pass that up. The only differance is he was dual exhaust lower unit. Can I run those props on my single exhaust LU?

Thanks,
Tom

 

[ondarvr]

Re: Single vs dual exhaust props

What is a dual exhaust prop or lower unit?

 

[pnwboat]

Re: Single vs dual exhaust props

Depends on the diameter of the bullet portion of your gear case that mates up to the propeller. Most of the dual exhaust units are 4 1/4" in diameter. Most of the single exhaust units are 4" in diameter. The splines (15) are the same. Only way to be 100% sure is to try it. Most of the dual exhaust props that I've tried on single exhaust lower unit won't work because they rub.

http://www.tacomapropeller.com/13009/Force-Outboard-Exhaust-descriptions.html

If you need some tips on interchanging, Frank A. has posted some examples that he has done to fit different props on his lower ends.

 

[SweeperForce]

Re: Single vs dual exhaust props

In 1989 Force had two different lower units. The single exhaust- the exhaust comes out the snout only. The dual exhaust- the exhaust comes out of the snout and though the hub. In addition, the water pick up are in two different areas. The SE- on the gear case, the DE- mid way between the gear case and the cavitation plate.

 

[Frank Acampora]

Re: Single vs dual exhaust props



English spelling lesson: I before E except after C. Friend. LOL

Your lower unit is most likely earlier than 1989 if it is single exhaust. Dual exhaust were made up until Mercury changed and installed a Mercury lower unit in the mid '90s. Thru-hub exhaust props used on dual exhaust lower units will fit and run on single exhaust lower units. There is NO difference in performance on a single exhaust lower unit between thru-hub and closed hub props of same pitch.--within reason. Different brands and models will run differently and stainless is always faster than the same aluminum prop.

However, some props MAY require removal of the anode, replacement with a smaller anode, or modification to the prop internal webs to correctly fit the lower unit. These are all props I use on my single exhaust engine. The first is a Vortex modified so it will fit. The last is an aluminum Mercury test prop again modified by cutting off the rear flange and epoxying it back inside the hub so it will plug into my lower unit.

 

[Frank Acampora]

Re: Single vs dual exhaust props



Couple more photos. I regularly swap single and dual exhaust lowers onto my engines. Last photo is a Mercury 2 blade bronze racing prop--old school

 

[ondarvr]

Re: Single vs dual exhaust props

In 1989 Force had two different lower units. The single exhaust- the exhaust comes out the snout only. The dual exhaust- the exhaust comes out of the snout and though the hub. In addition, the water pick up are in two different areas. The SE- on the gear case, the DE- mid way between the gear case and the cavitation plate.

OK, none of mine were in that age range, they had one or the other type of exhaust.