Sorry yall another overheater

[wht89gt]

so after lookin through all the threads couldnt quite find my exact problem. I have a 87 capri with a 3.0l omc motor and an omc cobra outdrive. Due to a blown head gasket i broke her down got it all machined and reasembled it new gaskets pistons rings whole rebuild any ways runs great turn the key fires right up. Well 3 things new impeller on it never started dry i took it out idled out ran great started getting hot then shot to 250 guage not thermo. I removed the thermostat still gets hot at my wits end with this boat took it out today idle out fine then bam smoking hot and makes a wierd bubbling gurguling sound when i turn it off in the inlet tube. Also the upper gearcase gets hot as heck exhaust mani is hot as heck and the cap at the beginning of the mani theres a drip in the cap had to run it back hot for a min then let it cool run then cool so on and so on but still stayed 200+. Also before i would grease the impeller only run it in water and the dang liner gets hot melts what i cant beleive is plastic and no one make even a pot metal one housing and turns in it cutting the water off to the motor gonna hook a hose to inlet tube tomorrow and make sure water is going through any help would be great or info also sorry about the sporatic sentences its late Thanks guys and girls for any help just want me and the youngins to get to enjoy this boat soon!

 

[flargin]

Re: Sorry yall another overheater

have you checked for blockages in your lines. If you toasted an impeller, those pieces run down the lines untill they get jammed in something. A fuel or oil cooler maybe?

there have been some suggestions to determine heating, I like the clear tube extensions, that way you can see if the water is flowing...

I don't know if this has a raw water pump but could you have the in and out switched?

it sounds like you don't have any water in the impeller housing, that is why you are toasting impellers.

Good luck.

 

[bruceb58]

Re: Sorry yall another overheater

Here are a couple tests:

Take out the impeller and try to force water down the hose at the thermostat toward the drive to make sure that is clear.

Pull the hose off the manifold for a few seconds to make sure water is flowing at that point. Only do this for a few seconds because the manifold will over heat.

Do you run your boat in saltwater? What is the condition of the manifold? A clogged up manifold won't allow water out so no water will get in.

 

[wht89gt]

Re: Sorry yall another overheater

Sorry. Its not a closed system forgot to mention it. Does water flow into the manifold? It used to fluxuate on temp now it just gets hot. Is there a flapper in this system seloc manual says check the flapper but doesnt show it at all. thanks for the replies guys

 

[bruceb58]

Re: Sorry yall another overheater

I think everyone understands it is not a closed system.

Just for information sake, water comes from your outdrive, though a cooler(power steering and or oil) and then up to your thermostat housing. From there, some of the water is circulated within the engine with the engine mounted circulating pump. The water exits the thermostat housing to the exhaust manifold. It goes through the exhaust manifold up and out the riser where it is combined with the hot exhaust gasses.

If you have blockage within the exhaust manifold/riser it will prevent new water from being delivered from the drive since no water will be exiting. That is why I want you to pull the hose off of the manifold to see if water comes out there.

I will ask my question again...has the boat been used in salt water?

There may be a flapper...that is if it hasn't melted from being overheated.

 

[flargin]

Re: Sorry yall another overheater

Sorry. Its not a closed system forgot to mention it. Does water flow into the manifold? It used to fluxuate on temp now it just gets hot. Is there a flapper in this system seloc manual says check the flapper but doesnt show it at all. thanks for the replies guys

Some boats have a flapper between the exhaust and the hull. I think your problem is a lot earlier than the flapper, I think you don't have water to your block or exhaust. If you do, it is not enough to cool the block(i.e. restriction)

Start at the front of the water system.

Go to the Adults only and download a real manual, thanks to Don S... use the seloc manual to clean the bilge out , the real manuals are a LOT better. It will show you how many screws your flapper has

I think you have blockage at or around your pump. Is your impeller in your outdrive or part of an external raw water pump?

 

[wht89gt]

Re: Sorry yall another overheater

Brackish im sure but before i owned it it was fresh only. Did a test today impeller is working fine water come all the way to t stat. Unplugged the line and fed water via water hose into the tstat end resuld bubble on elbo gasket and 4 flooded cylinders? All four were full fo water so mani gasket im guessing? I went ahead and pulled the head off water wasnt coming in from the headgasket no breaks or runs in the gasket

 

[wht89gt]

Re: Sorry yall another overheater

thanks for all the help guys

 

[wht89gt]

Re: Sorry yall another overheater

o and the manifold looks great very minimal signs of rust must be somewhat new. so im guessing exhaust leak or ...