Repower advice

[coastalcruiser]

My boat is a 74 23' Nisqually. It's got new transom, stringers. Has a 302 888 with a pre alpha leg that is made out of three drives, never did get the cooling problem solved so i'm giving up
Talked to a mechanic and he suggests a v6 220hp mfi with Bravo 2 drive. I have read most people would say get a v8 but the 302 is 188hp and it's fast enough.
any thoughts?

 

[mkast]

Re: Repower advice

Talked to a mechanic and he suggests a v6 220hp mfi with Bravo 2 drive.

Apparently you have a bunch of money.
If you in fact have that much money to throw at is 1974 hull,
why not get a 502?

 

[coastalcruiser]

Re: Repower advice

Mkast
asking for advice here, not sarcastic comments.
I don't know much but happen to know that a 351 will NOT replace a 302 as its wider so please don't make comments unless your sure.
Nothing worse than a smart guy that offers the wrong advice.

 

[chiefalen]

Re: Repower advice

I know this is not what you asked but maybe i can help you nail down the cooling issue and save you money.

Can you tell me what it is the cooling issue.

 

[coastalcruiser]

Re: Repower advice

Hey Chiefalen,
Thanks for the offer.
engine is a fwc 302 drive is alpha top lower is older maybe a r drive, transom is from a 4cly
So far i have had the manifolds risers exchanger cleaned out. Bubbles in coolant so head gaskets changed, leg taken off and double checked by mechanic, there is one new thermostat in the heatexchanger took the engine one out. it runs at 140f on muffs and in the water until it gets up on a plane. then the temp rises, and I back off *** soon as it gets up to 180 then it cools right down.
on the trailer if you leave the leg in the water boat out there is very little water comming out of the relief holes.
so although you can drive for miles at slow speeds it over heats on the trailer.
Mechanic suggested replacing circulating pump and I took it out but it's ok.
The boat is fast on plane loads of power. engine much better after head gaskets.
I have done lots of work and i'm thinking hey, its 30 years old, love the boat. and i have about 10k wouldnt it be nice to not have to work on this anymore...i put the whole package together form nothing but fixing it is beyond me...

 

[chiefalen]

Re: Repower advice

Some of these boats came with a flapper.

It's located in the exhaust tube.

If one broke off will block the exhaust.

Simple thing like that will block the exhaust and the symptoms will be as you described.

Don't give up you can do this. Sounds like your at your wits end.

That motor is a good motor.

One last time check to see if the freekin flapper broke off.

Some mechs don't even know what a flapper is.

 

[coastalcruiser]

Re: Repower advice

yes I found a flapper in the leg last year, happened to find it while i changed a melted down raw water pump.

I agree great engine, just ask boomyal and hautmedic!
I have heard bad things about 4.3 and read about mr don s replacing entire packages that overheat...ayuh

 

[chiefalen]

Re: Repower advice

You say you had a melted down impeller and you tracked down all the pieces?

Stupid question i'm gonna ask you, you take off the long hose coming from the transom, at the t-stat to see if you got good water coming to the motor.

Don't worry call me stupid if you want, Did you?

 

[coastalcruiser]

Re: Repower advice

You say you had a melted down impeller and you tracked down all the pieces?

Stupid question i'm gonna ask you, you take off the long hose coming from the transom, at the t-stat to see if you got good water coming to the motor.

Don't worry call me stupid if you want, Did you?

No such thing as a stupid question.
and I have nothing but respect

I just did the test at the boat launch last week.
The risers were too hot to touch after the sea trial, the long hose goes to the bottom of the heat exchanger. I guees thing to do is pull that hose off while on the trailer and start the engine that would tell me if its the heat exchanger or the leg has an impeller but stuck in the copper pipe in the transom assembly right?
I have run water from that pipe back down with the leg off seemed ok Could be a bad heat exchanger on the fresh water side...

 

[Bondo]

Re: Repower advice

and he suggests a v6 220hp mfi with Bravo 2 drive.

Ayuh,...
I understand wanting to go with the 4.3MPI, as it's a Great little Powerhouse...
But,...
Why on earth would you consider a Bravo II,..??
That drive is made for Barges,+ Houseboat type loads...
Bravo I, or maybe a Bravo III,..??
For that boat,+ 4.3l, an Alpha 1, Gen.II would be Plenty...

I have heard bad things about 4.3 and read about mr don s replacing entire packages that overheat...ayuh

I'm not sure what to make of that comment,...
I find it hard to believe Don would advocate Replacing the motor, for a simple Overheat,...
And,..
I truly Doubt that Don has ever uttered, nor typed the word, Ayuh...

I have run water from that pipe back down with the leg off seemed ok Could be a bad heat exchanger on the fresh water side...

That would have flushed out any debris, or remnants of the old Impeller...
I'd pull the Exchanger,+ have it Cleaned by a Radiator Shop...

 

[chiefalen]

Re: Repower advice

I typed a whole paragraph about the heat exchanger.

Then i went back and read the op.

Said he cleaned that out already.

So i deleted it before posting it.

Ok i might get jumped on. But here goes.

Latter for that heat exchanger.

In new boats nice.

Older boats nothing but a real royal pain.

Bond-0 has a very, very valued point. Yank it, take it to the garbage or a radiator place. Your choice.

But look at it this way if you take that out of the equation, does it fix the problem?

 

[coastalcruiser]

Re: Repower advice

I have another exchanger. This one i have is clean as a whistle on the raw water side. about a year ago i did swap the heat exchanger. but the cooling is tricky and that flapper may have been stuck in there when I did that.
so.. i'll check the flow on the ramp when I get back to town. if it's flowing good then i'll swap the exchanger, this wont cost me anything, at the same time i'll put a new t stat in at the engine. I just read a post its gotta be there i'm my case there were 2 t-stats when it worked fine...thanks for the support
Rob

 

[mkast]

Re: Repower advice

I don't know much but happen to know that a 351 will NOT replace a 302 as its wider so please don't make comments unless your sure.
Nothing worse than a smart guy that offers the wrong advice.

Hulls included Glastron, Hammond and Lund.
Original powerplants were a Mercruiser 188 (302).
We installed a 351, NO modifications required.
The base engine offered was a 302, the upgrade engine was a 233hp 351, from the manufacturer.
If the manufacturer knows that some hulls will be purchased with a 351,
just how much difference is there in the installation design?
By the way, I'm sure.

 

[coastalcruiser]

Re: Repower advice

sorry misunderstanding on my part
You can put a 351 in if ya want true dat
What I meant is you need to change the y tubes if you do

 

[mkast]

Re: Repower advice

What I meant is you need to change the y tubes if you do

If you are talking about the exhaust y pipe
No you don't.

 

[Cptkid570]

Re: Repower advice

coastal - this may sound basic, but when I changed the impellor on my alpha 1, rubber portions of the impellor actuall fell down into the bottom of the outdrive where the water gets sucked in. This stopped water from coming from the outside up to the impellor.

As Bondo and Chief said, before you spend a lot of money and replace everything, just turn it into a raw water cooled system and get rid of the exchanger completely.

To me, it just sounds like there is a clog somewhere. You obviously know a lot about working on this, so break it down into sections. 1. Is the water getting into the engine from the outdrive. 2. Is the water circulating through the engine. 3. Is the water exiting the risers and y-pipe. Too bad you don't have a spare set of exhaust manifolds and risers. How long has it been since you've changed those? That could be your problem.

Anyway, if you plan on replacing everything, you'll spend a lot of money going with a newer set up with a 4.3 versus just getting a remanufactured longblock from somewhere like rapidomarine. Plus, if you are going to spend the money, why go with a 4.3 liter 6 cylinder and not at least to a small block 8 cylinder like you have...

 

[Cptkid570]

Re: Repower advice

By the way... we'd love to see a photo of the boat

 

[chiefalen]

Re: Repower advice

Rob don't give up.

I posted this before you can do this.

I know the feeling just went thru my trail bye fire with my boat.

But i promise when it's all fixed and your on the water the first time and all is well with the boat, there is no better feeling.

You know you have achieved something very special. Something you can be proud of.

I wanted to quit also, you don't know how dejected i felt.

So don't quit use your intellect.

Go back to the basics.

Check that there are no obstructions in the drive, not allowing water up to the motor.

Check no obstructions in the t-stat.

No obstructions in the heat exchanger, if you chose to leave it, change it.

My opinion you already know i would put it aside, and take it out of the equation.

Risers good? Not blocked up?

No flapper blocking the exhaust?

T-stat new or left out till after you got it flowing good, the water and not overheating.

Engine mounted water pump good?

Back to the basics !

 

[Don S]

Re: Repower advice

The Nisquallies are nice small cruisers with lots of room inside (including head) Settee, flybridge and lower helm steering. Here is pictures of a slightly newer model. (Hopefully the same basic model)
http://www.classifiedads.com/boats-ad420791.htm

I think a 4.3MPI would do wonders for that boat, if it was hooked to a Volvo DP, not a Mercruiser Bravo of any kind.

 

[chiefalen]

Re: Repower advice

Very nice boat, worthy of restoration, and a wise choice.

However, the way to do it Don's way with new stuff would be expensive.

Around ten grand.

Simple over heating condition, with a simple fix here.

Enough motor for this boat.

I don't know about the op, but not everyone is wealthy enough to sink that kinda money in a 77' boat.