Johnson 1988 90hp still overheating Ahhhhhh

[scottygethotty]

Hi

Where do i start..

I bought a 1988 johnson on a 17ft bowrider, the engine was overheating so i replaced:

impellar
thermotats
new gaskets + cleaned out salt grime off of jackets
new plugs
fuel tank + leads
voltage regulator
water hoses

and its still overheating,, what next????

 

[wilde1j]

Re: Johnson 1988 90hp still overheating Ahhhhhh

You did a complete pump kit, right? and you're sure it's pumping?

 

[surrender]

Re: Johnson 1988 90hp still overheating Ahhhhhh

Does it have popit (spelling) valves? My 88 special does and they were not working when I first got the motor. I also did the change with how the tell tale is plumbed. I moved the outlet from the bottom of the block to the top of the starboard side. that helped with a definite hot spot i had. Have had no issues since.

 

[scottygethotty]

Re: Johnson 1988 90hp still overheating Ahhhhhh

im sure its pumping right the pee hole, pees!! sure it wouldn't pee otherwise?

What are popett valves and where are they on the engine?


my thought process is impellar turns throws water up to the engine block around the jackets into the thermostats then out the peehole right?

what else could hinder the temp

 

[Fed]

Re: Johnson 1988 90hp still overheating Ahhhhhh

Water deflectors.

 

[scottygethotty]

Re: Johnson 1988 90hp still overheating Ahhhhhh

water deflectors???? what exactly is or are they??. opps sorry just looked them up..

yes I done all four

 

[Cofe]

Re: Johnson 1988 90hp still overheating Ahhhhhh

Here is a link where Ezeke helped out in a similar situation. http://forums.iboats.com/showthread.php?t=323051

 

[scottygethotty]

Re: Johnson 1988 90hp still overheating Ahhhhhh

Thanks already seen that.

Question? do I have to put any sealer on the gaskets?

 

[Fed]

Re: Johnson 1988 90hp still overheating Ahhhhhh

Are you sure it's really overheating?
Can you test it with a heat stick or thermal gun thingie?
Does your alarm sound a continuous tone?
Did you put your hand on the heads to feel?
Are you 100% confident on the water pump job you did?

 

[scottygethotty]

Re: Johnson 1988 90hp still overheating Ahhhhhh

is there a possibility that the impeller is the wrong way round?

do i need gasket sealer ?

ALso and this is the annoying thing the thermostat is on constant after about 5 mins of running the boat, last week before the voltage rectifier blew up,. (my fault the battery wasnt grounded property) anyway, it was running like a demon before but still overheating now it splutters and the engine ceased up and had to wait for the engine to cool off before i could even move the flywheel by hand..

i just dont know what else to do ?? anything ??

 

[Fed]

Re: Johnson 1988 90hp still overheating Ahhhhhh

I read here in the forums somewhere that if you install an impellor with the vanes in the wrong direction they will correct themselves but I don't personally know that to be a fact.

You do need gasket sealer for the water pump bolts and the gasket under the plate below the impellor.

 

[Cofe]

Re: Johnson 1988 90hp still overheating Ahhhhhh

I have once seen head gaskets put on backwards. The water jacket holes in the gasket were then in the wrong place, making the heads over heat.

Not to say yours are in wrong, but your overheat problem is hard to diagnose. ...... Just wondering