Please Help Overheat problem

[jayh]

UPDATE AT BOTTOM OF THREAD OF WHAT I DID TODAY

mercruiser 5.7
alpha one drive

the boat overheats...if i take the boat over 3300rpms it overheats....if i gun it from a dead stop it over heats...if i take it up slowly in rpms i can sometimes get away with cruising for 10 minutes or so before it overheats....
i just had a bunch of work done to it recently i will list that below...
i can idle all day or drive slow and it will never over heat...
i took the thermostat out the other day and ran it around with out a thermostat....still it overheats....

work done
thermostat kit
thermostat sleeve
shift cable
gimble bearing
carb kit
spark plugs
exhaust flappers
exhaust manifolds
3 in spacer kit
riser gaskets
idler pulley
shift tower
water pump kit
gear oil
ignition coil
drive gasket


the impeller was replaced a few months ago.....


so anyone have any idea where i should start to get rid of this overheat problem?is there something that could be clogged?maybe impeller is screwed?i just blew like 2500 in work and im tapped out...its just sittin in the water collecting barnacles going to waste...lolol

 

[Don S]

Re: Please Help Overheat problem

What year? If it's a Gen II outdrive, did you have the impeller turning the right way? They won't flip over the right way.
Also look at your new water hose from the gimbal housing to the bellhousing. Is it kinked?
Do you have good water flow up to the thermostat housing

 

[jerryjerry05]

Re: Please Help Overheat problem

Pull the hose from the outdrive off and see how much water it's pumping.At an idle it should be fairly strong.Then rev it up and it should throw a lot of water.Do this in the water.The hose won't give you water.Jerry

 

[jayh]

Re: Please Help Overheat problem

im gonna try thois all in the morning...this problem has happened gradually over the lasy 2 months...i had all the work done then this just kept getting worse and worse every weekend

 

[jayh]

Re: Please Help Overheat problem

Pull the hose from the outdrive off and see how much water it's pumping.At an idle it should be fairly strong.Then rev it up and it should throw a lot of water.Do this in the water.The hose won't give you water.Jerry

its a 97 alpha one drive so i would assume gen 1?the impeller was changed back in jan..it ran fine for months then just 2 months agi started overheating

 

[Don S]

Re: Please Help Overheat problem

See what happens when you ASSUME , since it's a 97 it's a Gen II. The Gen I's as you call them, ended in 91.

 

[jayh]

Re: Please Help Overheat problem

See what happens when you ASSUME , since it's a 97 it's a Gen II. The Gen I's as you call them, ended in 91.

not sure what this does to help but i appreciatte all input!!!!

 

[Bondo]

Re: Nsk

Re: Nsk

not sure what this does to help but i appreciatte all input!!!!

Ayuh,..... It Defines what is being Worked on,.....
Which is a Good Thing, because You, the Owner doesn't Know what it Is.....

And,.... It's alot more Help than this Spammer,.....

Brother's great, I top you and I are also top-Jin top。

Hi- I am a completely worthless spammer
(edit) Nice edit Don,....

Did you Try the Test Jerry mentions,..??

 

[jayh]

Re: Nsk

Re: Nsk

im heading out to try this now ill let ya know what happens asap!

 

[jayh]

Re: Nsk

Re: Nsk

i tried the test...water was coming out the hose and when i revved it started shooting more..not sure how much pressure it should of been having though..

i took the hose off the water pump and the thermostat housing and inside of them were really corroded with rust...bad enough i could rub my finger on it and take chunks off...think that stuff could be restricting the water flow?

 

[Bondo]

Re: Nsk

Re: Nsk

think that stuff could be restricting the water flow?

Ayuh,...... It usually gets hung up in the Risers....

 

[jayh]

Re: Nsk

Re: Nsk

Ayuh,...... It usually gets hung up in the Risers....

im not sure what you mean by ayuh? the risers i have not changed but were inspected and the mechanic said they were good still

 

[jayh]

Re: Nsk

Re: Nsk

top

 

[jayh]

Re: Please Help Overheat problem

if anyone has any ideas for me please let me know

 

[Coors]

Re: Please Help Overheat problem

Take off all the hoses, risers, water jacket plugs, and get out all the crud you can, with picks, screwdrivers, a water hose...

 

[jayh]

Re: Please Help Overheat problem

I will do this asap and let ya know. Where are the water jacket plugs?

 

[Bondo]

Re: Please Help Overheat problem

Where are the water jacket plugs?

Ayuh,.....

They're found at the sides of the block, down low, just above the Oil Pan....

im not sure what you mean by ayuh?

Google is your Friend.........

 

[BAYLINER185]

Re: Please Help Overheat problem

I did the google thing as Ive been courious as well, I still havent got a clue but that doesnt stop me from reading and understand the rest of your posts lol....

Any way I think if you have a lot of rust and crap in there maby some of thats gotten trapped in the thermostst housing, although they said the thermo has been replaced maby theres still some crud in there??

Maby you can run a small wire through the water lines and see if maby you can clear up the passage and see if that helps. just a thought.

 

[jayh]

Re: Please Help Overheat problem

I'm gonna try all this in the morning. Thanks guys!!!

 

[Coors]

Re: Please Help Overheat problem

How do you winterize it, without knowing where the 5 plugs are?