Automotive to Marine project - Chevy 305.

[Brodacious]

Hello, and thanks for coming.

To make a long story short, I purchased a boat at the end of last season off craigs list. I know a good deal about boating and jack **** about engines. Turns out it has a chevy 305 with all automotive parts. :facepalm:

Over the winter I decided I was going finally learn about engines and fix her up so she runs safely and removing the "Exploding Hazard" so the old lady will get in the thing. I've read a lot about what needs to be done and have been collecting parts.

The exhaust was a Frankensteined mess. I'm pretty sure I've the manifolds worked out, the automotive ones are out, and I got some used ones off craigs list for a good deal. They were vented right out the back with huge exhaust ports. Looks cool but they might have to go, I don't think there is any check-value in them. Also saving up some cash for that 3" diam, $2 an inch marine exhaust hose... It must be gold coated in rubber...

The carb I've read a lot about and know it needs to be changed out. However, I've no idea what sort of carb I would need. There are 4 barrel and 2 barrel, which I haven't figured out which I'm going to use. Are there differences between v6 and v8 carbs? The carb thats in it now is, from what I can tell, a regular automotive carb that needs to go.

I know other things like the starter, altenator, water pump, should be changed. I'm trying to focus on the most return for my effort while not spending more than I paid for the boat.

Any tips or advice would be awesome.
The boat is a 17 foot 97 larson flyer.

Here is the "Before" engine picture.

 

[Don S]

Re: Automotive to Marine project - Chevy 305.

OMG, just enlarged the picture. That is scary, the exhaust system would set the engine compartment on fire, and the cooling system will not work at the way it's set up.
The guy that put that together was a total idiot.

Here is the OEM service manual for that engine http://www.4shared.com/document/Kgl-Dq7d/Service_Manual_17.html

Spend some time in the cooling and exhaust sections of the manual. I would also consider pulling the engine. I know it has steel core plugs in the block and there is no way you are going to change them with the engine still in the boat. Plus, you are going to likely need an exhaust Y or something for proper through hull exhaust that you know is going to work.

 

[Bondo]

Re: Automotive to Marine project - Chevy 305.

OMG, just enlarged the picture. That is scary, the exhaust system would set the engine compartment on fire, and the cooling system will not work at the way it's set up.
The guy that put that together was a total idiot.

Ayuh,... All I can say is Wow....

I agree, Nothing is Right, 'n Everything is Wrong....

Are there differences between v6 and v8 carbs?

Nope, not really,...
If ya go 4bbl., the Edlebrock 1409 is a Great carb, easy to tune, 'n works on any motor up to a BBC...
And, as far as boats go, reasonably inexpensive...

 

[Brodacious]

Re: Automotive to Marine project - Chevy 305.

Thanks Guys.

The old manifolds are off, and I'm going to be putting the ones in the pick below on once I get the correct bolts and some time, I have the risers also. I was thinking about using the existing ports out the back of the boat, rather than going with the Y since they are there and would be a pain in the *** to patch the holes.

As far as the Carb, I saw a 2bbl on craigs list from a v6 merc for 125 bucks. I'm kind of hesitant in purchasing a used carb, as I've no idea how to spot any sort of issues with it.

As far as the plugs go, I only plan to run her in fresh water, will that make a difference?
Where would I look for the plugs? I'll see if I can crawl in there this weekend and see if I can spot them...

thanks again guys.

 

[Don S]

Re: Automotive to Marine project - Chevy 305.

Love the name on the back of the boat. :facepalm: :facepalm:

 

[Brodacious]

Re: Automotive to Marine project - Chevy 305.

Hah, I know...
I Think I'm going to rename it "Frankenboat"

 

[Howard Sterndrive]

Re: Automotive to Marine project - Chevy 305.

I gotta think it would be cheapest to look for a boat with a rotten hull/missing outdrive etc, with a good running engine...or even a cracked block and then you'll have everything external... and a life size 3D model of where it all goes.

Trying to find every little bracket, shift interrupt switch, spring, fitting etc... is going to be tedious


You need to get rid of those exhaust pipes out the hull too... get a Y pipe with the donor boat.

 

[bloodyknuckletech]

Re: Automotive to Marine project - Chevy 305.

New to the board wanted to add my 2 cents..I see a lot of automotive swaps come through my shop and a common problem is intake gaskets..automotive gaskets have metal..marine gaskets are made with plastic..judging by how well this engine was put together I would be amazed if marine intake gaskets were installed..if metal ones are in there there gonna rust and possibly cause vacuum leaks and oil loss. Hope this all works out

 

[Bondo]

Re: Automotive to Marine project - Chevy 305.

New to the board wanted to add my 2 cents..I see a lot of automotive swaps come through my shop and a common problem is intake gaskets..automotive gaskets have metal..marine gaskets are made with plastic..judging by how well this engine was put together I would be amazed if marine intake gaskets were installed..if metal ones are in there there gonna rust and possibly cause vacuum leaks and oil loss. Hope this all works out

Ayuh,... Welcome Aboard bloodyknuckletech,.... (I Love the handle )

I hope the barges goin' through yer Shop were put together alittle safer, 'n cleaner than this 1 created with Bozo Engineering...

 

[Brodacious]

Re: Automotive to Marine project - Chevy 305.

New to the board wanted to add my 2 cents..I see a lot of automotive swaps come through my shop and a common problem is intake gaskets..automotive gaskets have metal..marine gaskets are made with plastic..judging by how well this engine was put together I would be amazed if marine intake gaskets were installed..if metal ones are in there there gonna rust and possibly cause vacuum leaks and oil loss. Hope this all works out

The intake gaskets on the manifolds?

 

[bloodyknuckletech]

Re: Automotive to Marine project - Chevy 305.

The intake manifold where yer carb is mounted..it bolts into the heads..on both sides port/stbd there's gaskets as long as the intake..I'm positive there automotive gaskets as a 305 automotive engine is cooled by antifreeeze..a marine engine is raw water..sometimes fresh water cooled..but even then id still recommend the marine gaskets as that engine compartment looks like it leaks bad..you can do more research on it if you want but there's a reason they made plastic gaskets for marine engines and rusting is the reason why..you can change them yerself if yer tool savvy and have a walk-through book handy..its definatley a weekend job..id recommend getting everything else done first before you address this issue..its not a major concern but it will cause problems later or possibly now if there already rusted

 

[bloodyknuckletech]

Re: Automotive to Marine project - Chevy 305.

Thanks for the welcome bond-o and I've seen worse

 

[RogersJetboat454]

Re: Automotive to Marine project - Chevy 305.

The intake gaskets on the manifolds?

The head gaskets may be suspect too, along with the aforementioned core plugs which are most likely steel rather than brass.

This engine screams late 80's GM from its aluminum intake with the thematic vacuum switch still installed to the center bolt valve covers, to the later style delco alternator with a serp belt. If the person who installed this monstrosity installed it as a complete engine, I bet it came from a Camaro. If it was cobbled together from all the parts he didn't sell at the swap-meet who knows.

In any case, for the edification and entertainment of both you and the others here, it would be interesting to figure out where this engine started it's life. If you get a chance some time see if you can find the suffix code on the engine. It would be stamped on the starboard side of the block ( left side when you face the engine) on a flat pad in front of the bank 2 (cylinders 2,4,6,8) cylinder head. You may need to take a stiff wire brush to it to bust the rust off of it to read it. Post that suffix code, and I may be able to tell you were that engine came from.

 

[Randy J]

Re: Automotive to Marine project - Chevy 305.

hi wel this diagram of original parts may be of some help?? i have sunbird with the OMC V-6 marine engine...

http://www.boats.net/parts/search/O...INTAKE MANIFOLD, EXHAUST & COOLING/parts.html

 

[RogersJetboat454]

Re: Automotive to Marine project - Chevy 305.

hi wel this diagram of original parts may be of some help?? i have sunbird with the OMC V-6 marine engine...

http://www.boats.net/parts/search/O...INTAKE MANIFOLD, EXHAUST & COOLING/parts.html

Randy,
Don't think that diagram is going to be much help to the OP. All that stuff is for a 5.0L Ford.

 

[RogersJetboat454]

Re: Automotive to Marine project - Chevy 305.

To the OP, after a second look at the pic of the tilted drive are we sure thats a Mercruiser drive and not an OMC cobra? Looks awfully gray to me in that picture....

 

[Brodacious]

Re: Automotive to Marine project - Chevy 305.

To the OP, after a second look at the pic of the tilted drive are we sure thats a Mercruiser drive and not an OMC cobra? Looks awfully gray to me in that picture....

The outdrive is an SX cobra

 

[RogersJetboat454]

Re: Automotive to Marine project - Chevy 305.

The outdrive is an SX cobra

May want to PM one of the mods and have this thread moved to the OMC I/O Forum

 

[Randy J]

Re: Automotive to Marine project - Chevy 305.

guess so after looking again dang! but rest of the y tubes etc looks same my gm v-6 has.. did all that r&r with flappers new hoses etc etc last year.. now to save up to get a new starter for the boat then back to riding again lol went from type 2 to type 1 diabities last month still issues with the insulin etc besides needing new glasses too! but im no lover of Ford products whew! Have a nice weekend !

 

[Brodacious]

Re: Automotive to Marine project - Chevy 305.

So, apparently the Carb on the Engine is a Edelbrock 1405 7296.

Would the simplest thing be to switch it out for a 1409?

Can anyone point me to some good carb resources? I'm trying to read up on the differences between the carbs and if I could possible learn enough to do it without botching it. I'm pretty determined to learn and am more than will to get my hands dirty. I'd just rather not make mistakes that cost hundreds of dollars. (already made the mistake of buying this tub, lest I can do is make it a good learning experience!)