Yamaha stern drive 4.3l replacement

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Kelsonj

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Ok well the boat made it thru most of the season. With a ton a help from the experts on this forum. Now I have another question.
I was not getting much power from the starboard motor. Idled good and ran under load but with a load won't get past 2500 rpm. I rebuilt the carb because the secondaries weren't opening and totally missed the fact that the secondaries didn't have the spring installed. So when they opened they fully opened and would not close.
So after getting the Holley's spring kit I reinstalled carb and fired it up. The engine hrdyolocked and I had water oil coming out of the #5 cylinder when I took the plugs out. Tried to do compression test but couldn't get the engine to spin period.
I pulled the engine and plan to do some repairs to the plumbing and the side of the engine compartment while it's out but I had a few questions.
The boat is a 92 Renken Seamaster 2688 with twin 4.3l and Yamaha outdrives.
-do I replace the Yamaha stern drive while the engine is out it seems to be in great working order but parts are bit hard to find if something breaks. It actually shifts great. Who would supply me with and outdrives and transom assembly package. New shift cable and remote I image as well$$$?
- do you all have any recommendations for an engine e supplier. Can a truck 4.3l work minus the external and freeze plugs.
The amount of milkshake coming out of #5 makes me think the water jacket is broken and not head gasket but I'm no pro. How to tell difference with out tearing it apart
- the exhaust manifold is gonna be replace with the fuel pump and starter should I budget anything else.
-any serious advice would be appreciated as this is only the second d time I be pulled a motor out of snything
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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the 4.3 is the least of your problems, and yes, a truck short block and heads will work fine

here is a good read on the 4.3 http://forums.iboats.com/forum/engi...history-of-the-4-3-liter-with-casting-numbers

if it was me, pull both motors, sell everything that says yamaha and replace with a carb-to-prop and controls mercruiser or volvo-penta setup for each hole. selling will allow you to recoup some money and allow another boater with a yamaha drive to get parts. all the drives have the same key-hole cut-out in the transom

go with '96 or newer motors and you get the vortec heads which is about 20 more hp.

btw, if you were boating in salt water, most likely the exhaust manifolds have failed and that is what is dumping water into your motor.
 

Kelsonj

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Mar 31, 2017
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That sounds like what I'm feeling Scott. This is my first project boat and what what a project. I have learned a lot but still rather ignorant. Who would I go to for the stern drive and controls. Does someone sell a complete stern drive exchange package.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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you can get new motors/drives all day long from mercruiser and volvo, however your going to pay new prices....or you can look around and find a couple of late 90's bayliners with rotten hulls and buy two of them, strip the motors out of them, dispose of the hulls and sell off the trailers.
 

Bondo

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Ayuh,.... Findin' 2 rotten boats with 4.3ls, 'n Alpha drives is no doubt the cheapest way out,...
Probably $3500. or under, each,...

Do a pulleys to prop swap, don't try to marry any of the Yamaha back in,...

Then sell all the Yamaha stuff to guys tryin' to get 1 more lap outa theirs,... probably get Great bucks for 'em,...
Anything left from the rotten boat deal is gravy,...
 

Kelsonj

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Mar 31, 2017
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Sure will tinman but I already removed the yems stuff.
Distubutors., Coil packs, computer. I'll pm you if I swap the drives. Pm me if you want any of the engine management stuff
 

Malmsten

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Jul 29, 2019
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I'm about to swap my YEMS ignition to something more reliable. What did you choose? Do you know if the Mecruiser HEI distributor work plug and play?
 

southkogs

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This topic is two years old and the OP hasn't been back in a while. Malmsten please start your own topic.

This one is closed.
 
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