One side (STARBOARD) overheats on 1987 Ev 90 HP

[bang4dabuck]

This is a project I've been working on for too long. This boat is sitting in my fathers driveway. I have never put this MOTOR in the water. Two summers ago I changed water pump and therms. I also rebuilt carbs. Last winter I changed out head gaskets and DEFLECTORS. I also put on a temperature sender on EACH head. I ran it for the first time this summer in the driveway for a few minutes. Port side was fine got up to 100ish but starboard went to about 180. I turned her off when it hit about 160 but it continued to climb. When should my BRAND NEW ALARM go off, BTW ???

OK, what did I do wrong or what did I not do ?

 

[levi_tsk]

Re: One side (STARBOARD) overheats on 1987 Ev 90 HP

right about 180....
are you sure youve got good water flow? those impellers dont like it when you make em sit dry for a year and then ask them to pump water efficiently .... might wanna go ahead and get just a new impeller and see if that fixes it

 

[emdsapmgr]

Re: One side (STARBOARD) overheats on 1987 Ev 90 HP

You will get an overhead horn when either cyl head gets to 212 degrees. The horn will shut off when it gets back down to 175. Even that is too hot. Your engine should idle around 140 to 150. Since you changed the impeller, deflectors and stats already, you may have other issues. Was there any debris/crud buildup around the cylinders when you replaced the deflectors? You may want to the head cover off the hot head and see if you have debris buildup in it which will restrict water flow.

 

[emoney]

Re: One side (STARBOARD) overheats on 1987 Ev 90 HP

Did it run long enough for the T-stats to open? I had my 140 on muffs in the driveway, starboard side got past 165 and it worried me, so I shut it down. Everybody convinced me to put it in the water with an IR guage and that's what I did. Once she was in the water and the t-stats opened, temp dropped down to a consistent 140-150 on both sides with the starboard being just a smidgeon warmer.

 

[bang4dabuck]

Re: One side (STARBOARD) overheats on 1987 Ev 90 HP

On the IMPELLOR, why would one side be cool and the other hot ???

What is an IR GAUGE ? What temperature did the thermostats OPEN UP finally at ???Could my one thermostat be stuck due to sitting around too much and needs to be pushed a little ? Maybe I got some glue on it.

I cleaned the heads and head covers pretty good. There was a lot of that white aluminum corrosion. I did not notice any other build up.

Anybody got a good diagram of the water flow ? I'm thinking clogged passage or stuck (brand new) therm. What do you think ?

 

[levi_tsk]

Re: One side (STARBOARD) overheats on 1987 Ev 90 HP

On the IMPELLOR, why would one side be cool and the other hot ???

What is an IR GAUGE ? What temperature did the thermostats OPEN UP finally at ???Could my one thermostat be stuck due to sitting around too much and needs to be pushed a little ? Maybe I got some glue on it.

I cleaned the heads and head covers pretty good. There was a lot of that white aluminum corrosion. I did not notice any other build up.

Anybody got a good diagram of the water flow ? I'm thinking clogged passage or stuck (brand new) therm. What do you think ?

the water come into the left bank and fills up the right bank and then flows out on these engines its common for the right bank to be hotter due to the way the water flows though the engine BUT at the same time its also common to do serious damage due the the thought that "oh it s a little warm its normal" it isnt

MOST PROBABLY the blades on your impeller have "taken a set" from sitting and the blades are permanently bent and are causing you reduced water pressure

listen to me on this one as ive chased this ghost before.... a simple impeller change wil most probably fix this problem

an IR temp gauge is what emoney is talking about it reads infared radiation to give you a temperature reading without the need to touch the block - they make em in a handheld version for about 25 bux

 

[bang4dabuck]

Re: One side (STARBOARD) overheats on 1987 Ev 90 HP

Thanks, thats why I always come here first for pointers and advice.

I have 2 FARIA HEAD TEMPERATURE SENDING UNITS (one for each head) so no need for IR gauge (although I do have one just for this).

So when I pull IMPELLOR anything I should be looking for ? The thing was installed almost 2 years ago and only has been started up a couple times since then.

 

[itsaboattime]

Re: One side (STARBOARD) overheats on 1987 Ev 90 HP

The starboard side will always run hotter on muffs. Put it in the water and go. The temps will just about even out while underway. The waterflow while underway is alot more than on muffs and the motor will cool more efficiently. I too chased this ghost on my '87 110 horse 'rude.
A 2 year old impeller is due to be changed, regardless if it has been run or not. That impeller will, like previously stated, will have a curved "set" to the blades. It may even be cracked in the blades. The rubber "ages" under the stress of being curved inside the housing.

 

[emoney]

Re: One side (STARBOARD) overheats on 1987 Ev 90 HP

When looking at the impeller, check for cracks in the splines and drying out in the same. Also, if it's bent in one direction and doesn't want to "un-bend", meaning it's lost or is losing it's flexibility, then assume it's time. In saltwater, we change our impellers out once a year. Even in fresh water use, it's recommended every two years. Also, sometimes it's worse for an outboard to sit than it is to be used. Lots of seals, gaskets, rubber parts to stiffen up and be useless. I'm not near my manual, but I'm pretty sure remembering the T-stats opened up once she went past 165. I could be wrong and it might've been 180, so don't bet the bank on that. If noone weighs in with better information, I'll try and see if the OEM Service Manual mentions what temp they open.

One other suggestion; if you have access to (or have one) a 55 gal drum or a large enough trash can that you can put the outboard in and submerse it in water, it will be a lot cooler than the muffs. It's recommended to NOT rev it up much on muffs, so submersing will allow you some leeway there, but make sure you keep a hose in it, if you're going to put strain on her or if she goes into gear because any outboard, especially a 90, can empty a 55 gal drum full of water in seconds.

 

[1946Zephyr]

Re: One side (STARBOARD) overheats on 1987 Ev 90 HP

I would remove the t-stat entirely and run it for a few minutes and see if it still gets hot. If it does, then you have a blockage in a water passage going to the bank that gets hot. It's possible that a blade from a previous inpeller could have broke off and shot up inside of the water passage and blocked it off. It's possible that you may have to pull the powerhead to investigate this issue. I have seen all kinds of interesting things in outboards, when it comes to cooling issues.

 

[bang4dabuck]

Right now, it looks like the first thing I'm going to try is find a big trash can

Right now, it looks like the first thing I'm going to try is find a big trash can

that the lower end will fit in. Again what temp should I shut her down at, 160 ?

If that doesn't work pulling the therms seems like the next step.

If still hot pull head and if cool check the one thermostat and put therm assembly back on and hope it runs cool. If it still runs hot replace impellor.

Sound good ?

 

[levi_tsk]

Re: Right now, it looks like the first thing I'm going to try is find a big trash can

Re: Right now, it looks like the first thing I'm going to try is find a big trash can

that the lower end will fit in. Again what temp should I shut her down at, 160 ?

If that doesn't work pulling the therms seems like the next step.

If still hot pull head and if cool check the one thermostat and put therm assembly back on and hope it runs cool. If it still runs hot replace impellor.

Sound good ?

like has been said the motor will run hotter on the hose change the impeller and go for a ride if you can ... if it shoot up over 175 still then you got problems and need to shut it down but even out on the water the right bank will run a little hotter (about 10 degrees F) this is due once again the the way the that cooling water flows through the block

water flows from the t-stat housing into the far left side of the left bank up and over the number one cylinder down the other side of that bank up the left side of the right bank and back down the right side of the right bank and down the leg and out of the exaust