engine swap from 6cyl to 4 cyl

boaterinsd

Petty Officer 1st Class
Joined
Nov 19, 2010
Messages
276
i have the 1973 aq170 now with a bad head. I am able to get a 70's aq130 for nothing but the time it takes to remove it. Now is the ratio in the outdrive gonna need to be switched or can i do a prop change to make it work.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: engine swap from 6cyl to 4 cyl

Yes, you will need to change the gear ratio.
 

PiratePast40

Lieutenant Commander
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Mar 21, 2009
Messages
1,734
Re: engine swap from 6cyl to 4 cyl

I am able to get a 70's aq130 for nothing but the time it takes to remove it.

Cracked heads are common so make sure you take the time to check out the engine. At the very least, pulling the head to inspect and lap the valves is a good idea. Rebuild parts like rings, valves, cam and bearings are available but they are dependant on the serial number of the engine and it may take a bit of research. I'm just finishing up on a rebuild so don't hesitate to ask questions.

You can swap out outdrive lower ends for the gear ratio change but reshimming may be required.
 

boaterinsd

Petty Officer 1st Class
Joined
Nov 19, 2010
Messages
276
Re: engine swap from 6cyl to 4 cyl

ok, so your boat with the 4 cyl is how big and have you had it running before? Since mine was always not right i believe it should be fine since its an older boat anyway, right. Has anyone got a good running 4 cyl aq130 in there boat? And if so what is the performance you get with it?
 

sqbtr

Senior Chief Petty Officer
Joined
Feb 23, 2010
Messages
716
Re: engine swap from 6cyl to 4 cyl

I run a 130 in a 17.5 foot boat, 34 mph gps is max
 
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