165hp Merc Swap to Chevy 250 Vacuum Advance?

josh42177

Cadet
Joined
May 1, 2018
Messages
12
I just swapped a Mercruiser 165hp with a chevy 250 truck engine. I replaced all the marine parts and the engine started right up. The chevy truck motor has a vacuum advance on it's distributor and the Merc motor doesn't. I'd rather not swap it out because I hate doing timing and dealing with points. Can I plug it up and or just leave it as is? It idles great. I need to get the drive system on before I can get it to normal operating temps and test acceleration, etc.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,265
you need a marine distributor in your boat to prevent things from exploding

you also need brass core plugs and a marine cylinder head gasket as well as a marine circulating pump and marine starter, alternator and accessory brackets and pulleys.
 

Lightwin 3

Petty Officer 1st Class
Joined
May 18, 2010
Messages
300
Agree with all. Especially the distributor.

If you're in salt or brackish water the other components will last, maybe, a month.
 

josh42177

Cadet
Joined
May 1, 2018
Messages
12
thanks... only fresh water here. I did end up swapping the distributor. I was worried about the timing, but i was able to get it on the first try.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
There is no vacuum on a boat. You need mechanical advance.

An automotive distributor has the same mechanical advance as a marine distributor.. It's just that the marine distributor has no vacuum advance (because a marine engine is usually always under load, so a vacuum advance would never be activated), and the marine distributor has all the 'stop it going bang' mods....

Chris..........
 
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