2004 johnson 25 hp S.L.O.W.

[HotRod Lincoln]

hello all i have a 2004 johnson 25 hp TESRA. i've got a problem and i've worked on it all week and can't figure it out. ok every time i take my boat out my motor will run about 5-10 minutes and then when reved up to high rpms, the motor shakes real bad and has no power and runs like crap. if I idle down to lower rpms it runs fine. i've read that this is due to the S.L.O.W. mode. When i un-hooked my temperature switch it ran fine, when I plugged it back in the S.L.O.W. kicked back in. So i removed the back cover and i replaced the temperature switch with a new one, and while i had the cover off, i replaced my thermostat, spring, o-ring also. When i did this my boat ran like a top for 1-hour for two days in a row but now today it started it all over again. but this time i felt the back cover and it was pretty darn hot, i couldn't hold my fingers on it at all. so now that i feel that it really is getting hot but i have a good stream of water coming out the side and my intake screens are clear. where do i go from here? is the water pump going bad? please help God Bless

 

[Daviet]

Re: 2004 johnson 25 hp S.L.O.W.

The tell-tale only indicates that the water pump is pumping water, not that the water is circulating through the block. I wounder if a t-stat is not opening properly. It wouldn't be the first time a new part failed.

 

[boobie]

Re: 2004 johnson 25 hp S.L.O.W.

Have you had the g/c off and checked/replaced the water pump??

 

[Rick.]

Re: 2004 johnson 25 hp S.L.O.W.

As a temporary measure you could try running without a stat. Would not recommend that for the long haul but only to eliminate it as a potential problem. Best of luck. Rick.

 

[HotRod Lincoln]

Re: 2004 johnson 25 hp S.L.O.W.

i have not checked my water pump. that was next on my list. i think i will take the cover back off and remove my thermostat and see if that eliminates the problem. if not i guess i will assume its a bad water pump.

 

[Rick.]

Re: 2004 johnson 25 hp S.L.O.W.

It is also possible you have a bad sensor putting it into slow mode. I would change the impeller if you don' know when it was done last. Rick.

 

[HotRod Lincoln]

Re: 2004 johnson 25 hp S.L.O.W.

ok i replaced water pump (water pump rebuild kit), and it is still getting hot. i've still got flow out of tell-tale and i felt the back cover plate and it is definately getting hot burnt the heck out of my finger as soon as i touched it. and i've replaced the temperature sensor and the thermostat. so i am assuming my line is plugged between the tell-tale and the thermostat, but i am going to remove thermostat tonight and and then run it to see if it still gets hot.
if i find that the line is plugged, how is the best way to clean it out? with compressed air? and to clean it out i assume i have to drop the lower unit and unplug copper pipe from water pump housing?

 

[Rick.]

Re: 2004 johnson 25 hp S.L.O.W.

With the stat removed run it in a tank and see how much water you get at the stat opening. Also try back flushing from the stat location with a hose. If you do drop the leg then you can hook a make shift hose connection to the water tube and try flushing with some pressure. If none of that works you should remove the head and see what's happening .> you may need to pick the passages clear. Hope to hear your making progress. Rick.

 

[HotRod Lincoln]

Re: 2004 johnson 25 hp S.L.O.W.

ok i removed back cover and removed thermostat and left the back cover off while i started motor in barrel of water. When i started the motor i had absolutely no water come out the thermostat but there was lots of water coming out of the very small bottom compartment. according to my manual the water shouldn't be in the bottom compartment untill after going thru the thermostat. so from what i can guess is a water deflector must be bad, and the water is going around the deflector and into the bottom compartment while "bypassing" the thermostat i guess? i will try to add picture showing the bottom compartment i am talking about

 

[HotRod Lincoln]

Re: 2004 johnson 25 hp S.L.O.W.

ok here is a link to pic...ignore my finger the black box is where the water was coming out

http://i1122.photobucket.com/albums/l532/hotrodlincoln7/boatmotor2.jpg

 

[HotRod Lincoln]

Re: 2004 johnson 25 hp S.L.O.W.

Figured it out!!!!! ONE OF THE WATER DEFLECTORS WAS MISSING!!! it has 3 two long ones and short one, the short one was missing and all the water was basically bypassing the thermostat. hopefully it got flushed out and ain't still in there somewhere. THANKS for all your help you guys rock!