overheating

[1stevel]

Hi Guys,
i need some help with an overheating issue. I have a 1990 4.3 mercuriser and as the engine temp goes up it don't stop and im not sure if water is getting into the engine it starts smoking like all heck and i have to shut it down. how can i tell if the water pump on the stern drive is working or what should i be checking first. any help would be appreciated.

 

[180shabah]

Re: overheating

You need to run it on muffs to "SEE" any water discharge.

If you had smoke coming from the engine compartment, then it was most likely the rubber exhaust components burning due to lack of water.

When was the seawater impeller last replaced?

 

[1stevel]

Re: overheating

I'm new to boating and thanks for the reply, I did run it with the muffs on but i don't know where the discharge would come out. it did have a rubber smell to it when it was smoking so i i guess i need to replace the parts you are talking about. i don't know any history of the boat as the original owner has passed on and i am learning as i am going along, the motor seems to look in good condition.

 

[180shabah]

Re: overheating

i don't know any history of the boat

Then it is time to back WAY up, before you really destroy some expensive parts. I/O's are pretty maintenance intensive. There is a long list of items that need to at least be checked, but most will need to replaced now since you can't verify how long they have been in service.

Water pump impeller, bellows, gimbal bearing, ujoints, engine alignment, full/complete tune up, fuel filters, rubber exhaust components (due to heat damage), t-stat, belts, hoses, engine oil, drive lube etc......

 

[180shabah]

Re: overheating

..missed your "question" about cooling water discharge. You have an alpha, some will dribble out through the prop hub, but most will just DUMP from the idle relief ports on the transom shield. There will be a LOT of water - should be the same amount as if you turned the hose on and let it run.....

 

[1stevel]

Re: overheating

i ordered the water pump kit for the out drive, any idea what rubber parts need to be replaced on the exhaust? i would like to order them too so i can do everything at once.

 

[1stevel]

Re: overheating

i was wondering where the water exited, i really didn't see any water coming out of the motor just the over spray from the muffs.

 

[Don S]

Re: overheating

i was wondering where the water exited, i really didn't see any water coming out of the motor just the over spray from the muffs.

If the water isn't getting into the engine, it sure won't come out.
What you need to do is pull the outdrive and then seperate the upper from the lower and inspect the pump and see what the problem is.
The reason you need the drive off is so you can check some other very important stuff.
Have you looked at any of the information in the Adults only and DIY stickies at the top of this forum (FIRST 2 Threads in this forum)
You should.

 

[1stevel]

Re: overheating

This Saturday i will be pulling the out drive, it looks easy enough, and yes i have been reading the adults only section,downloaded the manuals and I'm learning a lot on this site not just from your advice but all the problems other people have and what they have done to rectify the problems they are having.

 

[180shabah]

Re: overheating

post what you find.