mercruiser overheating

[peter paul]

hi im new to the post thread but here it is i have a 1982 470 mercruiser 4cylinder and it overheats. Ive change the thermostate.removed the heat exchanger cleaned it out checked if timming was of adjust 4to 5 degree starts up nice one shot. checked hoses if callopes non found. when it heat up it start overfilling my resevoir tank with the pressure cap on. if i remove the pressure cap it come out the from the tank wher i fill it up. now my last check was if i was getting stream of flow with motor running no flow could it be my water pump. i put a hose to run it it come out thru the exhaust out propeller. please advise me what should i check or replace im lost.

 

[Eric 3.7LX Alpha 1]

Re: mercruiser overheating

Disconnect the hose at the voltage regulator which is the 1st thing water from the drive hits, put muffs on and see if any flow. (engine off)

 

[peter paul]

Re: mercruiser overheating

Disconnect the hose at the voltage regulator which is the 1st thing water from the drive hits, put muffs on and see if any flow. (engine off)

ok i will do that but could you explane to me how would it work. i see hoses going in and out. so if i diconnect it and water flows good do that mean that regulator isbad.

 

[Eric 3.7LX Alpha 1]

Re: mercruiser overheating

behind the regulator there is a piece of 1/2" copper pipe about 6" long, it is strapped to the backside of the regulator so the cool seawater can help cool the regulator. Water just flows thru that pipe on it's way to the heat exchanger. I doubt it is blocked there, but will tell you if there is some kind of restriction in the drive as that is the first thing the seawater from the drive hits.

How old is the impeller?

attached is a pic of the backside of the regulator:

 

[peter paul]

Re: mercruiser overheating

i don"t know i bought the boat 3 years ago. if the regulater is clogged thats why it overflows threw the resevoir. cannot be the water pump. sorry to question you but trying to square everything how it work i appreciate your helping me.

 

[abrx7]

Re: mercruiser overheating

The impeller should be changed every 2-3 years. I would that to your project list as well.

 

[peter paul]

Re: mercruiser overheating

The impeller should be changed every 2-3 years. I would that to your project list as well.

one thing i also notice that when it was in the yard i had it in it did not overheat ran it so many times but as soon i park it in the street it started overheating my street is kind of steep but i raise the bow, and thought it was air in the system i was wrong.

 

[Eric 3.7LX Alpha 1]

Re: mercruiser overheating

I would start with a new complete water pump kit in the drive, since it's at least over 3-years old. 470's don't take well to overheating, they have a tendancy of blowing head gaskets when they do.

 

[peter paul]

Re: mercruiser overheating

o boy the water pump kit u talking about is the front of motor or the outdrive do you have a picture of the outdrive pump is it something i could handle or do i have to take it to a marine mechanic.

 

[Don S]

Re: mercruiser overheating

Here is how you replace the raw water pump in the drive.
This pump is the FIRST thing you check in any boat with an overheat problem. All it takes picking up a plastic bag over the intake while boating and you can damage an impeller if you don't catch it immediately.
Being your first time replacing it, I would suggest you remove the drive from the boat. I have a feeling that hasn't been done and the splines greased yearly as they should be.


View attachment A1 Impeller replace.pdf

 

[peter paul]

Re: mercruiser overheating

Here is how you replace the raw water pump in the drive.
This pump is the FIRST thing you check in any boat with an overheat problem. All it takes picking up a plastic bag over the intake while boating and you can damage an impeller if you don't catch it immediately.
Being your first time replacing it, I would suggest you remove the drive from the boat. I have a feeling that hasn't been done and the splines greased yearly as they should be.


View attachment 152322

do i need special tools or pulleys or press

 

[abrx7]

Re: mercruiser overheating

Nope. Just some wrenches, sockets, and beer.It's a very simple job. Just make sure that you replace every o-ring.

 

[Eric 3.7LX Alpha 1]

Re: mercruiser overheating

Here are a couple of videos for you check out, let you know what you are up against

Seperating the Upper Gearcase from the Lower Gearcase
http://youtu.be/kfpasFN_g8w

and another
Mercruiser water pump removal and repair video
http://youtu.be/0QC6_j2_wmA

and also download that link Don gave you. It is very detailed and from the repair manual.
Couple of other things:
don't forget to put the remote shifter in forward when you pull the drive,
and you have to hold the lower half in forward gear when you mate the halves back up.

 

[peter paul]

Re: mercruiser overheating

Here are a couple of videos for you check out, let you know what you are up against

Seperating the Upper Gearcase from the Lower Gearcase
http://youtu.be/kfpasFN_g8w

and another
Mercruiser water pump removal and repair video
http://youtu.be/0QC6_j2_wmA

and also download that link Don gave you. It is very detailed and from the repair manual.
Couple of other things:
don't forget to put the remote shifter in forward when you pull the drive,
and you have to hold the lower half in forward gear when you mate the halves back up.

thank for every detail you guide me i removed the outdrive and seperated it just like you mention i found the pump fin gone not there and found exhaust particle in it i turn the propeller gear upside down to shake what in it not much came out should it be concern in other things i should do before i install it back together. thanks a much your the boat man.

 

[Eric 3.7LX Alpha 1]

Re: mercruiser overheating

I can't take credit for the videos... I stumbled on them myself and felt they would help give a little confidence to tackle the job.

If you were missing any parts of the impeller, they may be lodged furter upstream and can cause flow issues. You will want to try and find it before you reinstall the drive. This is were the early posts come into play.. pull that hose on the voltage regulator and stick a garden hose there and blow backwards to the transom, it will come out the large O'ring on the bellhousing where the water passage is and see how the flow is. Hopefully you can find that missing piece.

 

[peter paul]

Re: mercruiser overheating

o yes that part of the regulater that you mention come in handy i will remove the hoses and back flush thank for whole lot i will keep in touch with progress.i will pick the pump tomorrow and go from there.

 

[peter paul]

Re: mercruiser overheating

o yes that part of the regulater that you mention come in handy i will remove the hoses and back flush thank for whole lot i will keep in touch with progress.i will pick the pump tomorrow and go from there.

hi how you doing im back i removed the outdrive and seperated and removed the pump it had no impeller left pieces came out installed all seals and o rings. the only question i have is the water pump impeller when pushing it in the houseing which way the fin should be turn. does it matter

 

[Speakrdude]

Re: mercruiser overheating

Doesnt matter. As soon as the shaft spins the fins will correct themselves.

 

[peter paul]

Re: mercruiser overheating

Doesnt matter. As soon as the shaft spins the fins will correct themselves.

man you just save me headace thinking about if i install it wright. did not start it up yet cause it in my neighbor lot and dont want to distub him useing his water but i still have to change the oil and filter while im at it no rush. i will keep u informed that alot again.this sight is great.

 

[achris]

Re: mercruiser overheating

You do need to account for the missing parts of the old impeller... They could be lodged in the heat exchanger or the exhaust elbow. Blocking any part of either of those items will reduce the cooling on the engine (It'll overheat under load)... While you have the drive split apart check the water pocket cover....

Chris.......

If you don't know what a water pocket cover is.... -> http://forums.iboats.com/showthread.php?t=556903&p=3825409&viewfull=1#post3825409