1984 mecruiser 470

[Live-liner]

Re: 1984 mecruiser 470

I did mine myself.
The manifold that failed was too far gone, so I had to find a good used one and mill the surface of that one. The surface should be very close to the size of the gasket all around and there cannot be any pitting or etching on it. You cannot use sealant to make up the differance. I see you are in Mass. If you don't want to pay for a new one (who does)Check the RI craigslist under boats, there is a guy in Richmond RI that posts an ad (search 3.7) he normally has a few kicking around.
Good Luck

 

[jabfd]

Re: 1984 mecruiser 470

I did mine myself.
The manifold that failed was too far gone, so I had to find a good used one and mill the surface of that one. The surface should be very close to the size of the gasket all around and there cannot be any pitting or etching on it. You cannot use sealant to make up the differance. I see you are in Mass. If you don't want to pay for a new one (who does)Check the RI craigslist under boats, there is a guy in Richmond RI that posts an ad (search 3.7) he normally has a few kicking around.
Good Luck

thanks for the reply i am looking for one used i emailed that guy waiting to hear back. i thought of using a belt sander to take alittle off . i put the oem gasket in i started at 15 psi overnight and this morning it had droped down to 13 so i still have a slight leak trying to get this boat back in the water .

Does anybody know if the oem gasket has to be warmed up for it to seal better ?

i put new gasket but manifold is still off the boat . i also pressure tested the engine with manifold off and it held 15 psi for over two hours until i took the tester off so that sholud rule out head gasket.

thanks for everbodys help

 

[jabfd]

Re: 1984 mecruiser 470

update update

I found a used manifold aluminum and riser pressure tested and is held .

since i pressure tested the engine before i put manifold back on to 15 psi and it held this should rule out head gasket or any other possibly leak right ?

And last now i have a rough idle and stalling condition could this be points ? also i left the key on the on position for days and it killed the battery this was done when i pulled the boat out of the water . thanks for your help this is a really good site

 

[mr 88]

Re: 1984 mecruiser 470

You fried your points when you left your key on. Replace,set gap and dwell to spec and if you carb is clean it will idle like new.

 

[jabfd]

Re: 1984 mecruiser 470

Update I changed the points and it idle a lot better and did not stall when I looked at my old points one contact had a hole thanks for the reply

 

[jabfd]

Re: 1984 mecruiser 470

Took the boat for sea trial and it is running good but idle a little when I replaced the points I just gaped them to .18 the tag on valve cover said between .18 and .25 should I set it in the middle or is .18 good I don't have a timing light but I think my father has one some where he is looking for it

 

[stonyloam]

Re: 1984 mecruiser 470

You should get a dwell meter too. Setting the gap is OK, but a dwell meter will do a much better job. About $30 but well worth it if you are keeping the points ignition.

 

[jabfd]

Re: 1984 mecruiser 470

Hi guys. So I put the boat in the water after all of this and aim still losing a/f. Oil looks clean I pressure test the new /used exhaust manifold before I installed . Also pressure tested engine and it held 15 psi so wtf is my a/f going !!!!! Could the head gasket leak only when warmed up I pressure tested the engine with it cold . Since the exhaust manifold was off. Thanks for all our help

 

[harleyman1975]

Re: 1984 mecruiser 470

possibly the heat exchanger is rotted?

 

[stonyloam]

Re: 1984 mecruiser 470

possibly the heat exchanger is rotted?

Could be. You could test by draining the raw water side and then pressurizing the antifreeze side and see if any antifreeze leaks into the raw water side of the exchanger. If it does you have a leaky tube.

 

[Eric 3.7LX Alpha 1]

Re: 1984 mecruiser 470

It's not going to rot though, it made of copper I believe. Tubes can be soldered closed if necessary. It will work just fine with a tube soldered closed on each end.

 

[Live-liner]

Re: 1984 mecruiser 470

Yes, all copper.
I believe the manual states that you can block off three tubes MAX. I would have to look it up, but fairly certain.