One head over heating

[emdsapmgr]

Re: One head over heating

Unlikely any misses at 2000 are related to the overheating issue. Try putting an inductive timing light on each plugwire at 2000 rpm. The timing light should show any misses or nofires on each plug wire. If you don't see any issue with the spark, it could be a lean condtion in the idle jets. It's called a lean sneeze. That's a carb issue. Caused by dirt/debris in the idle jets/passages in the upper carb body. A can of aerosol carb cleaner sprayed through each passagway will clear that up. Also, remove all jets and check them visually to be sure they are open/clear. Those carbs don't have midrange jets, make sure you pull out the pullover jets. Also, check to make sure you don't have any fuel mixture spraying back out of any carb throats (cracked/broken reed.)

 

[bmstang]

Re: One head over heating

Thanks i appreciate it i will look into it. I guess the main thing right now is getting that head to cool.

 

[beverly]

Re: One head over heating

For those stripping bolts you can always repair the threads with a Liquid Thread Repair.. Not recommended for heads, I did this on a lawnmower. but if the head isn't leaking then leave it. just bring a wrench with you on the water incase those bolts start giving problem and the motor misfires on that cylinder.

If you can't sell the motor and wanna use it till the end, JB/weld it in place.

Another thing you can do is go the next bolt size up. Tap and Die.

Water blockage... C.L.R. or Lime Away but would hate to see if theres damage on the impeller from the stuff. I wonder if you can purposely block one side and see if there pressure. Could test this with air or vacuum and listen if it leaks or not. This works for car engines to see if the valve's close up tight. But in your case, there should be air flow.

 

[bmstang]

Re: One head over heating

I did try form a thread made by permatex but that didn't work as far as moving up a bolt size i need to be careful i don't want to crack the block i really don't know how thick the walls are. Thanks

 

[bmstang]

Re: One head over heating

Update the lean sneeze is fixed turned out to be the plugs. I had put a set of NGKS in and the person at the store gave me the wrong plug. I looked in my shop manual and found the correct number for the plugs problem solved what a relief the motor never sounded so good. Now as far as the head over heating i took out the thermostat and pressure valve again on that side started her up water is flowing real good i am now able to put my hand under the water with out burning it just luke warm. When i closed everything back up it gets real hot to the touch i can put my hand on the head and water cover for about 3 seconds and i have to pull it off. I rechecked the thermostat and it's working i don't know if there is a way to check the pressure valve to see if it's working and if it's not can that be causing it to run hot . I was thinking about removing it to see if it still runs hot with out it in and can i possibly run with out one.

 

[emdsapmgr]

Re: One head over heating

Doubtful the pressure relief valve has any effect on an overheat at idle. Those valves open when the water pressure in the block increases-such as when the boat planes out. Those valves stay closed at idle and all the water flowing thru the block goes thru the stat only. Did you ever have a look inside the block between the cyl banks?

 

[bmstang]

Re: One head over heating

No i haven't got around to looking in the block because i need to go rent a puller and haven't had the time right now to get around to it. I was told i need to be careful taking that cover off considering the age and corrosion i really don't want to break any bolts but i will get around to it probably next weekend. One person locally told me if i could hold my hand on the head for at least 3 seconds that's normal. I am making progress though because like i said i could at least hold my hand under the water now what's confusing is why when i close it up it gets hot.

 

[emdsapmgr]

Re: One head over heating

You might want to rent a laser temp gun from a local auto parts store and find out just how hot the head is really getting. The stats open up at 143, and normal head idle temps in summer waters can run up to about 150-155. When you get on plane and those pressure relief valves open, the head temps will plunge dramatically, as the head will fill with a lot of fresh,cool lake water. An overheat (hot horn) sounds at 212, and the overheat switches will cancel the overheat alarm when the head temps get back down to 175. (which is still too hot for normal operation-my humble opinion.) I would not rely on any temperature feel from the telltale, as that is water that comes from the exhaust cover, one of the first places that gets incoming water from the pump impeller. Also, a stong telltale indicates a good impeller, but does not indicate that either/both stats have opened in each head.

 

[kenmyfam]

Re: One head over heating

Agree with the infra red thermometer suggestion. You will then know for sure what you actually have. It is also a great tool to find a "hot spot" on your motor.

 

[bmstang]

Re: One head over heating

Thanks i will look into renting a laser gun most likely next weekend thanks for the leads i will keep you updated

 

[bmstang]

Re: One head over heating

Update i was able to get my hands on a laser gun. The head that i thought was running hot is at 143 deg so putting in the new deflectors and cleaning the water cover helped. The power head and the other head are running around 100 degrees. The cylinders on the side running 143 are about 150 degrees. Now do i need to bring the cool side up to temp i wonder if the thermostat is stuck open

 

[bob johnson]

Re: One head over heating

Update i was able to get my hands on a laser gun. The head that i thought was running hot is at 143 deg so putting in the new deflectors and cleaning the water cover helped. The power head and the other head are running around 100 degrees. The cylinders on the side running 143 are about 150 degrees. Now do i need to bring the cool side up to temp i wonder if the thermostat is stuck open

was the test dont on muffs at idle rpms???

it may not get hot enough with cold well water and only idling

I dont know if I have ever heard of a T-stat sticking open...I have heard of them sticking closed.

I know even at wot my heads never go above 120 with the T-stat out!!!

good luck

bob

 

[boobie]

Re: One head over heating

I have seen t-stats stick open especially in salt water areas.

 

[itsaboattime]

Re: One head over heating

My '87 110 horse will run hotter on one side. The starboard side runs 143 degrees and the port side runs 120 @ idle on muffs.
On the river both sides run about even.
I have been told by several people that this is normal.

 

[bmstang]

Re: One head over heating

I checked it in the water no muffs on. Idle was about 1100rpms i will pull the t-stat cover off and check it i guess it's better running cooler than hotter. Thanks