1990 Johno 140hp V4 overheating at 3500 rpm

[ratbag's]

I have a mate having problems with his '90 Johno overheating when he goes over 3500 rpm.

Thermostat replaced.
Water pump replaced.
POP Valves replaced.
Heads removed, new gaskets.
Exhaust manfold removed, cleaned & new gaskets.

Still have the overheating problem after all this.

Model: 1990
HP: 140 V4

Any suggestions appreciated. Thanks, Ratbag

[backlash08]

dumb question but how do you know its getting hot?

[FNQCairns]

No not dumb it's a good question.......SPLASH!!!!!! where are you?????:)

cheers fnq

[39NESP]

had the same prob at 3200 revs did all the same as you but when i took cover plate off port head it was full of hard salt
cheers snapper

[Chris Ryan]

I had a 115 Johnno V4 that did the same thing. Ausfisher Chimo gave me the good oil, had to shorten the thermostat springs a tad. They are a two stage thermostat and don't open fully until very late in the heat and rev range.

Chris

[Donny Boy]

What area are you in Ratbag ??
If anywhere near the Gold Coast, I've got just the man to speak to.

[Noelm]

OK, as I said on the other site, you need to know if it is over heating for sure, not a false alarm, from there we must assume that all the bits replaced have been done correctly, other wise we have two problems now, so find out if it is getting hot for sure and get back to us.

[ratbag's]

thanks everyone, appreciate the heads up!

Don - we are in Gippsland (East Vic region), I am happy to call someone in Qld to get this fixed.

we know it gets too hot, can't touch motor, & the alarm goes off.

Cheers, Ratbag. :o

[Donny Boy]

Know it well matey,.............. old Vic boy meself. Saw the light & here we am.

Aaaahhhh Queensland .....Beautiful one day.............all out for 93 the next !!

But I digress..................

The guy is B J Rowling. ( BJ ) Water Torque Marine 0402 492554.

I have exactly the same motor on mine, and B J has got it running like a Ferrari..
He's pulled it to bits, rebuilt it, added & changed bits, put on & taken off other bits, modified bits..........mate,......... HE KNOWS...!! ::)
Young bloke but very good !! Speaks plain English too !! :o

He should at least get you heading in the right direction.

Good Luck mate. :thumbup: ;)

[ratbag's]

Know it well matey,.............. old Vic boy meself. Saw the light & here we am.

Aaaahhhh Queensland .....Beautiful one day.............all out for 93 the next !!

But I digress..................

The guy is B J Rowling. ( BJ ) Water Torque Marine 0402 492554.

I have exactly the same motor on mine, and B J has got it running like a Ferrari..
He's pulled it to bits, rebuilt it, added & changed bits, put on & taken off other bits, modified bits..........mate,......... HE KNOWS...!! ::)
Young bloke but very good !! Speaks plain English too !! :o

He should at least get you heading in the right direction.

Good Luck mate. :thumbup: ;)
thanks a million Don! Boat lives in Gippsland, I in Melb mon-fri, work pays for the fishn! will call BJ and see what we can do.

Tight lines for Christmas.