1997 johnson 90 at full throttle runs at 180 degrees

[mike58]

1997 johnson 90 at full throttle runs at 180 degree and when idling goes right back down to 130 or so is this normal and no horn comes on either thanks for any help, mike ps just put new water pump in and have PLENTY of stream

 

[bob johnson]

Re: 1997 johnson 90 at full throttle runs at 180 degrees

it is a 60 degree motor?

I have the same motor in 115 and have had the same issue... I have done all kinds of tests, replaced the t-stats, impeller, installed dual water temp senders and dual temp gauges, i have installed a water pressure gauge.

I checked and compared readings from a top of the line infared thermometer...

I have run the motor with out t-stats, I have ran it with one t-stat and then the other side alone...

I have posted several threads here on the same subject, no one seems to want to reply to them...

my hot head is the port head.

my mechanic though it might be the higher elevated head (vertical not temperature) that was getting hot, because maybe the water could not get all the way up there at speed, but that isnt the case.

i have 30 psi at WOT...I did discover the trim angle helped a little


maybe a new water pickup, like the racers use, is my next step..

it is definately a water restriction thing...via the t-stats..

if you take the t-stats out the head never see 125 degrees!! but the water pressure never topped 10 psi...mainly because of no back pressure..

if you leave one t-stat out, the temp on that head never goes above 120, but the other head, goes for 200 fast!!!

all the water is blowing right by the front of the t-stat and there is too much pressure needed to try and get through the small openings and as such NO water goes that way!!

I am thinking about opening up the holes in the t-stats, EQUALLY so they both see the same pressure...

one step for me is to pop the heads and look for passage restriction in that head

I read another thread where guys squirt dawn detergent into the garden hose then hook it up to the muffs and has the water push the dawn through the engine...I think ill try that with no t-stats so i can get a lot of volume

teh dawn disolves salt resdue

good luck

I hope you get more replies than I did

bob

 

[SparkieBoat]

Re: 1997 johnson 90 at full throttle runs at 180 degrees

I think the horn goes off at somewhere just over 200 degrees. you can test your over heat horn by grounding the tan wire coming from your temp sensor on the engine block. 180 does not seem to be over heated to me, I think its normal to have a rise in temp at WOT. Someone else may weigh in and confirm. you also can have a blockage somewhere. is temp the same on both heads??

 

[SparkieBoat]

Re: 1997 johnson 90 at full throttle runs at 180 degrees

Bob, you should run motor with both stats in or out, not one in and one not. if its running 125 with out them, I would just stay with that. or try making the holes bigger like you mentioned.

 

[bob johnson]

Re: 1997 johnson 90 at full throttle runs at 180 degrees

I said my trim adjustemtn helped, but now that I think about it it was lowering the motor on my hydraulic jack that helped as much as the trim..

but I suspect something isnt right, because both heads should be the same..

on my motor one always runs hotter

the plugs look good..so i doubt I am running lean...

I use my motor in the dead of winter mostly, and Ill need those t-stats.

besides i subscribe to getting it running like it is supposed to, and if it isnt, then ill try hard to solve why it isnt..

what i foundwhen i removed them was that extra water flow is all that is needed..

so i figure ill leave the t-stats in and no extra water will pass through them UNTIL they open...then i want more flow...maybe the larger holes will help.

my mechanic says its a pain to reinstall those BIG O-rings in the heads ...

so i am trying to avoid that unless nothing else works

bob

 

[SparkieBoat]

Re: 1997 johnson 90 at full throttle runs at 180 degrees

o-rings not too bad..I use the black gasket adhesive stuff to hold the rings in place..works great for me...It would be worth it to pull the heads and check for blockage, and that the deflectors are in place, they can slide down and block part of the head.

 

[bob johnson]

Re: 1997 johnson 90 at full throttle runs at 180 degrees

o-rings not too bad..I use the black gasket adhesive stuff to hold the rings in place..works great for me...It would be worth it to pull the heads and check for blockage, and that the deflectors are in place, they can slide down and block part of the head.

I dont think the 60 degree, eagle block motors have deflectors......do they??

I cant see anything that could be considered a deflector on the schematics..

not like the 90 degree motors which have the fingers in the water passages..

I dont know what #11 is because it is NOT listed in the parts names and price sheet


PS that item #11 isnt on the 95 and 96 year motors but appears to be on later models( mine is a 1995)
bob

 

[SparkieBoat]

Re: 1997 johnson 90 at full throttle runs at 180 degrees

good question..maybe they dont have deflectors..still could be sand or other blockage..it would be worth a look if your bolts are not seized up. use anti sieze when you replace the bolts, and maybe even replace with stainless bolts if they are not already.

 

[bob johnson]

Re: 1997 johnson 90 at full throttle runs at 180 degrees

good question..maybe they dont have deflectors..still could be sand or other blockage..it would be worth a look if your bolts are not seized up. use anti sieze when you replace the bolts, and maybe even replace with stainless bolts if they are not already.

I think all the bolts on the ocean runner and ocean pro models were stainless steel...

I am not sure about the fastrike and intruders( but they didnt come in 90 hp, like the OP has, so it dont matter)

he may well have a crossflow motor!!

 

[SparkieBoat]

Re: 1997 johnson 90 at full throttle runs at 180 degrees

he may that was never specified I guess. In any event it is fairly common to get sand/corrosion blocking water jackets. if everything else fails, pull the heads, and clean.

 

[mike58]

Re: 1997 johnson 90 at full throttle runs at 180 degrees

thank you every one who replied I`m gonna try the thermostat's and it is a 60 degree motor thanks again Mike

 

[bob johnson]

Re: 1997 johnson 90 at full throttle runs at 180 degrees

speaking of thermostats...I have the factory manual... and it shows what looks to be 4 or 5 pieces that make up the parts under that big plastic nut that holds the t-stat in....

but when i took mine out it was a once piece covered t-stat and a spring....

and when i bought new ones at the marine mechanics shop he gave me ones that looked just like what i had in there...

I wonder if they made a change somewhere along the line and they dont sell what originally came with the motor any more( whats in the manual!)...

I cut one open today...not much room for water flow inside!!

there is what looks to be a normal looking t-stat inside the cream colored outer housing...

the 2 in my 97 90 hp look just like the 2 that were in my 95 115 and just like the 2 new ones i bought....

I may alter one to see if I can get more flow when open

bob

 

[SparkieBoat]

Re: 1997 johnson 90 at full throttle runs at 180 degrees

I have a 89 200 HP motor in which I took the plastic t-stat housing apart and removed the spring and the actual t-stat, put housing back together and reinstalled..runs around 130 degrees at WOT