First boat with big problem

[shouldsellit]

Was hoping my first post on this site after getting my first boat was not going to be like this.

I have a 78 fiberform with a merc 470 i/o.

So the problem is taking it out first time was fine for about an hour then all of a sudden engine would cut out at high rpm's. Did that twice then i noticed that temp gauge was maxed and lots of steam coming out the stern.

Docked it and noticed the antifreeze reservoir was bone dry. Filling it up but it would never get full but did not see where it was leaking from. At that point looked at the outdrive and saw the antifreeze coming out. My buddy jumped in the lake and it was coming straight out of the impeller

So after a lot of searching through site found possibly that the heat exchanger has a hole in it or a blown head gasket. Pulled the heat exchanger and called around to boat places and radiator shops but nobody says the have the equipment to test them

Only thing I could try was putting a hose on one end and running compressed air through but it seemed to only go out the appropriate sides for antifreeze and seawater.

Dont know if it will tell me anything but am going back today and doing a compression test. If it is a blown head gasket how is it getting to the outdrive?

Any help would sure be appreciated or any additional information needed, would be checking this thread often today.

Thanks

 

[shouldsellit]

Re: First boat with big problem

That was my conclusion after going through the cooling section in the merc manual but I figured was just missing something.
Will try to block it better and try it again.

 

[Rocky_Road]

Re: First boat with big problem

Was hoping my first post on this site after getting my first boat was not going to be like this.

I have a 78 fiberform with a merc 470 i/o.

So the problem is taking it out first time was fine for about an hour then all of a sudden engine would cut out at high rpm's. Did that twice then i noticed that temp gauge was maxed and lots of steam coming out the stern.

Docked it and noticed the antifreeze reservoir was bone dry. Filling it up but it would never get full but did not see where it was leaking from. At that point looked at the outdrive and saw the antifreeze coming out. My buddy jumped in the lake and it was coming straight out of the impeller

So after a lot of searching through site found possibly that the heat exchanger has a hole in it or a blown head gasket. Pulled the heat exchanger and called around to boat places and radiator shops but nobody says the have the equipment to test them

Only thing I could try was putting a hose on one end and running compressed air through but it seemed to only go out the appropriate sides for antifreeze and seawater.

Dont know if it will tell me anything but am going back today and doing a compression test. If it is a blown head gasket how is it getting to the outdrive?

Any help would sure be appreciated or any additional information needed, would be checking this thread often today.

Thanks

As a fellow 470 owner, I can promise you one thing...your overheating has ruined the head gasket. A compression test will show you that, and not get you any further in your coolant issue.

My money is on the heat exchanger leaking into the raw water path. Your next move will be shopping eBay...but you are 'rolling' the dice, as to getting one any better than yours. Some radiator shops can fix these...but if yours is the older 3" exchanger, your best bet is to get a newer 4" exchanger. They can be had new (last time I searched the net, I found at least one company selling them...try Breezeworks http://www.breezeworks.net/).

Sorry to meet you under these conditions....

 

[Rocky_Road]

Re: First boat with big problem

To my knowledge, the only place that the anti-freeze and the raw water come together is the heat exchanger.

To test it, block the anti-freeze outlet and pressurize it on the input side to 15 PSI. My bet, the leak will quickly become apparent.

You would be right Bubba...except that his head gasket has to be compromised. He needs to correct that, before any coolant pressure test.

The 11th commandment for 470 owners: thou shalt replace the head gasket, if thou goeth too long with the fire and brimstone.

Edit: your test will work, Bubba...I should have read all of your wise words!

 

[stonyloam]

Re: First boat with big problem

sounds like a pretty big leak. I would think that the easiest way to check it out would be to drain the exchanger seawater side (aft plug on bottom), and then fill the reservoir with dyed water and see if it comes out the seawater drain hole. I agree the head gasket is probably toast.

 

[shouldsellit]

Re: First boat with big problem

After testing exchanger again i felt some air out of the seawater ports, which would be then bad i assume?

I am on my way to boat to do the compression test and sounds like a new head gasket, fantastic.

Will let you know, thanks

 

[stonyloam]

Re: First boat with big problem

The replacement gasket should be OEM Mercruiser, more expensive, but I believe it is engineered specifically for the 470 to seal better.

 

[Rocky_Road]

Re: First boat with big problem

After testing exchanger again i felt some air out of the seawater ports, which would be then bad i assume?

I am on my way to boat to do the compression test and sounds like a new head gasket, fantastic.

Will let you know, thanks

If you go the new gasket route...use the Mercruiser part.

Proven to be the best...!

Good luck!

 

[wajajaja02]

Re: First boat with big problem

for the heat exchanger, go on line,google heat exchanger, there are shops that will make what ever custom exchanger you want, my neighbor does them for a living for the drug industry, made one for my wood furnace /hot tub during his lunch break as a thank you for plowing his driveway.

 

[shouldsellit]

Re: First boat with big problem

As a fellow 470 owner, I can promise you one thing...your overheating has ruined the head gasket. A compression test will show you that, and not get you any further in your coolant issue.

My money is on the heat exchanger leaking into the raw water path. Your next move will be shopping eBay...but you are 'rolling' the dice, as to getting one any better than yours. Some radiator shops can fix these...but if yours is the older 3" exchanger, your best bet is to get a newer 4" exchanger. They can be had new (last time I searched the net, I found at least one company selling them...try Breezeworks http://www.breezeworks.net/).

Sorry to meet you under these conditions....

As far as overheating did to the head gasket. Compression test showed 120, 120, 125, and 120.
I am not sure but that seems like it is ok and in range of each other, what do you think?

Also it seems reading the replies that the only way for that coolant to escape to the outdrive is the heat exchanger, am i correct on this?

Not sure what else to check if there is anything or at this point bite the bullet and purchase another exchanger.

 

[shouldsellit]

Re: First boat with big problem

for the heat exchanger, go on line,google heat exchanger, there are shops that will make what ever custom exchanger you want, my neighbor does them for a living for the drug industry, made one for my wood furnace /hot tub during his lunch break as a thank you for plowing his driveway.

Is a "custom" exchanger better way to go?
Found a 4" merc for $400 online.

 

[Rocky_Road]

Re: First boat with big problem

As far as overheating did to the head gasket. Compression test showed 120, 120, 125, and 120.
I am not sure but that seems like it is ok and in range of each other, what do you think?

Also it seems reading the replies that the only way for that coolant to escape to the outdrive is the heat exchanger, am i correct on this?

Not sure what else to check if there is anything or at this point bite the bullet and purchase another exchanger.

I'm impressed...you are the first 470 owner that has 'steamed' his engine, and his head gasket lived to tell about it! You have broken the 11th commandment, and this qualifies you to start your own Church of the 470 Survivors....

Dittos on the heat exchanger path...number 1 reason for losing coolant.

As for having one 'made'...I don't see it. As long as there are new ones out there....

Can I get a "Hallelujah", Reverend Shouldsellit???

 

[shouldsellit]

Re: First boat with big problem

I'm impressed...you are the first 470 owner that has 'steamed' his engine, and his head gasket lived to tell about it! You have broken the 11th commandment, and this qualifies you to start your own Church of the 470 Survivors....

Dittos on the heat exchanger path...number 1 reason for losing coolant.

As for having one 'made'...I don't see it. As long as there are new ones out there....

Can I get a "Hallelujah", Reverend Shouldsellit???

Hallelujah!
I don't think i have ever been happier to shell out $400. Sounds like it could have been at lot worse.
Just to check I pulled out the exhaust elbow just to see what it looks like, looked good.
I will put a order in for a exchanger, and will update after that.

Thanks again to everyone for help, always nice to be part of a site that helps out and responds quickly.

 

[Rocky_Road]

Re: First boat with big problem

Hallelujah!
I don't think i have ever been happier to shell out $400. Sounds like it could have been at lot worse.
Just to check I pulled out the exhaust elbow just to see what it looks like, looked good.
I will put a order in for a exchanger, and will update after that.

Thanks again to everyone for help, always nice to be part of a site that helps out and responds quickly.

Reverend,

I'm not waiting until your Sunday meeting...here's my tithe, to your righteous cause:

 

[shouldsellit]

Re: First boat with big problem

Reverend,

I'm not waiting until your Sunday meeting...here's my tithe, to your righteous cause:

Haha I saved the pic its a keeper.

 

[stonyloam]

Re: First boat with big problem

Congratulations on dodging the bullet! Once you are up and running with the new exchanger, check the little weep hole on the lower starboard side of the circulating pump on the front of the engine. If you see coolant leaking (while the engine is running) you will need to replace the camshaft/waterpump seals. Keep an eye on that coolant level. Welcome to the (470) club!

 

[bigskiohio]

Re: First boat with big problem

first boats should not be 470s what i have readabout them scares me.

 

[stonyloam]

Re: First boat with big problem

...... what i have readabout them scares me.

Me too and I have had one for 18 years

 

[shouldsellit]

Re: First boat with big problem

Congratulations on dodging the bullet! Once you are up and running with the new exchanger, check the little weep hole on the lower starboard side of the circulating pump on the front of the engine. If you see coolant leaking (while the engine is running) you will need to replace the camshaft/waterpump seals. Keep an eye on that coolant level. Welcome to the (470) club!

Now a proud member of 470 club whether I like it or not

Exchanger is on order and will update statis when its all put together again.

 

[shouldsellit]

Re: First boat with big problem

***Update***

I pulled my exhaust elbow again because something just didn't seem right when I would pour coolant in and it would never fill up, just shoot out the out drive. Seems like it would be more of an issue then the heat exchanger with the rate I am loosing it.

Here are the pics I took of the elbow and the gasket with metal plate in between. Can somebody please explain to me why there are three jackets for the coolant to come out of the exhaust manifold but the plate is blocking two of them??? This does not make any sense.

Might be hard to see but first pic shows plate that blocks both the sides but top is open to allow coolant to flow.
The second pic shows the exhaust manifold that connects to the elbow with coolant showing on all three jackets.