Overheating

[Zook4184]

Hello everyone I just bought a 1987 88spl evenrude outboard I put it on my pontoon hooked it all up started it up ran about a minute alarm sounded started it back up after letting it cool ran again but this time hit with laser temp gun and starboard side heated rite up to 200 degrees alarm sounded port side stayed below 150 deg also water pump pumping strong so replaced stats poppets springs also ran with 2 hoses off of heads had equal amount of water flow coming out pretty solid put it all back together ran it several times for 15 to 20 minutes no overheating checked head with temp gun both below 150 degrees this is where it gets me lake day backed down the ramp started it up let it idle while parking truck and trailer my buddy said 5 minutes into idling alarm sounded shut off let cool started back up figured take for a ride ran it at all full throttle all different speeds for 10 minutes or so no alarm decided to take to slip started across the lake 5 minutes into it alarm sounded let it cool started up got it to the slip let it run at the dock no alarm sorry for long post but I’m not sure what to do next other then pulling back out of water and pulling heads any ideas would be greatly appreciated or next steps to diagnose thanks scott

 

[racerone]

Step #1 is a compression test after numerous overheating incidents.-----A rule to follow is a new impeller on a new purchase.

 

[Zook4184]

Step #1 is a compression test after numerous overheating incidents.-----A rule to follow is a new impeller on a new purchase.

Ok thank you I will check compression it was 120 give or take a pound on all 4 cylinders before starting when purchased but I will drop drive and check pump I did check it while in the lake it was solid the whole time maybe it is not strong enough

 

[racerone]

The water from the tell tale DOES NOT circulate through the block.----There may be internal blockage in water jackets.-----Tabs on head gaskets are on outside on both heads?----Pictures ?

 

[racerone]

That manual shows pictures of a 4 HP model.-----The factory manual would not confuse or mislead you !

 

[Zook4184]

The water from the tell tale DOES NOT circulate through the block.----There may be internal blockage in water jackets.-----Tabs on head gaskets are on outside on both heads?----Pictures ?

The water from the tell tale DOES NOT circulate through the block.----There may be internal blockage in water jackets.-----Tabs on head gaskets are on outside on both heads?----Pictures ?

Ok thanks for reply I tried load short video but didn’t work but I will get pics tonight and post of outside of heads

 

[Zook4184]

Ok I got heads off totally caked with salt and sand deflectors swollen piston walls in good shape I see at the top where I think the water comes in but I also see a small round hole in the cavity does water flow thru there also

 

[Terrapin]

The swollen water deflectors are most likely the major contributor to your overheating. Pull your water deflectors and clean up the water passages around the cylinders. Be sure to protect your cylinders from the dirt. A small wire brush on a Dremel motor tool can help clean the passages. Open up any small round holes (it may be an air bleed? not sure) using a twist drill sized a few thousandths of an inch smaller than the hole.
Replace the water deflectors with the proper replacement part numbers. Lubricate the water deflector and cleaned cavity very well with oil to help you get the full tube length in place. A pick like tool with a 90 degree bend on the end can help. Pierce the tube about 1/4' from the tube end that will enter the block first and use the pick to push the deflector fully into the block.

 

[Zook4184]

Thank you for your advise I really appreciate it definitely know the pic your talking about