1996 Evinrude E88TSLEDR - Overheat - Starboard Side Not Flowing Well

[SeaBisket]

1996 Evinrude E88TSLEDR having an overheat problem. Boat came out of the water and hit high RPMS, 5 mins after = overheat HOT light. I thought I'd spun or killed the impeller, since it didn't overheat @ 1k RPM and let me limp in. Bursts to 3k triggered HOT light.

I pulled the water pump impeller was good shape but did come off the bushing pretty easy. I replaced the whole water pump and launched the boat. Overheat sounded at 1k after 7 mins. Tell-tale was good the whole time.

I read some messages, especially interested in the thermostat and water deflectors. I hooked up the flush ears, pulled the hoses off from the head to the thermostats, started and observed: Steady flow on PORT, intermittent, spitting on STARBOARD side. Could keep finger on PORT side head, but STARBOARD = too hot to touch.

Here's a pic of the flow:


Unsure what to expect on PORT, but I know spit and steam is not ideal.

Pulled the STARBOARD head. Observed swollen deflector:

Also observed top STBD piston crown a little chowdered, same for head. Bore / cylinder was smooth.
Piston:

Head:


Unsure how long was like this as this, but this cylinder was @ 80 PSI compression since I got it in 2016, with all others @ 110-120 - so I figured was old news and I moved on.

I replaced the deflectors. Here's the one of note, which can block things:


Popped head back on w/ new head gasket and getting same result - spitty flow out of STARBOARD. I didn't let HOT light come on, but could keep finger on PORT and STARBOARD was getting hot. I have attached FlowVideo.mp4 to show the differences.

I pulled the head after testing to ensure my thin-walled deflectors didn't move; they didn't.

I thought I am ruling out the thermostats as they are AFTER such flow. Let me know if I am badly mistaken by this. I have a whole thermostat kit, but thought wasn't issue if nothing coming out of heads. It's a tight on this motor..

Are the thermostats (or the things in the thermostat housing) passing water through the galley and INTO the heads? If so - then I wouldn't be surprised it's the root-cause.

I also observed that the head has a breach:


I wasn't sure if that was an issue, either, but I thought that would present as exhaust gas in the water. Either way - $40 on ebay = a new head coming.

I also wanted a sanity check on the head gasket orientation. Given this is STARBOARD, this is correct, right:


Thank you all for your time and efforts. I am very curious about the thermostat flow and if I am even performing a valid test.

 

[racerone]

No point going any further.---Classic broken rings syndrome.-----Motor needs to come apart to replace with o/s pistons.---4 of them.

 

[SeaBisket]

Ya racer, thanks! I did some searching about the piston stuff.. Ring piece(s) flying around the chamber, eh?

Still curious about the water flow passage stuff, though. Is the thermo unit in the flow prior to the heads?

This is calls for a full rebuild, right? I am total green @ rebuilds, but I wanted to make sure I am looking at the right scope. All this stuff, right?

Can I get some opinions here?

Rebuild kit = $830. Powerhead = $2100. Boat and motor was $3.8k. I got about $1k into whole thing (trailer rebuild, electronics, batteries). It's June 2021 and boats are stupid expensive and unavailable right now. To me - this is worth me trying a rebuild. The hull's old but real sound. The motor's steering arm is super corroded and I'd need to pull powerhead to replace that anyways. This is a no-brainer right? Rebuild kit? Seems like it to me.

Thanks again!

 

[racerone]

Yes that is what you are looking at.-----Properly done your grandkids will be running this motor.----These motors are scoffed at by some.----But seeing it was running with that kind of damage means that these engines are well built with just one flaw.----That being the design of the top piston ring.

 

[SeaBisket]

Thanks! Been doing more research and you've really helped a lot around here! Do you have any really awesome videos, or must-read online threads in your virtual toolbox? I'd appreciate any reference materials.

I have the factory service manual, plus a SELOC book. I found a cool vid showing the powerhead pull @

Thanks again! Curious to see how I make out. Having the internet changes things so much, and thanks to all the contributors!

 

[racerone]

You have to be really careful with internet presenters.----One was trying to take a V-4 apart and was hammering taper pins in the wrong direction.----Then on another video he was trying it on a V-6.------I learned about these broken rings back in about 1980 and I can rebuild one without looking at a manual.----Just nuts and bolts and common sense.

 

[SeaBisket]

Awesome. How many hours do you estimate for you to do it, on average.. I know conditions vary. I say it's 12 hours for a first timer like myself, esp given salt use..

 

[racerone]

Double that estimate.----Time taken from removal of first bolt to turning the key to start it.----And likely more.------You need to go over carburetors.----Starter motor.----Fuel pump.-----Cylinder head covers.

 

[SeaBisket]

Cool.. last question.. do I need to magnaflux block as mandatory? Could I do a leak down test like I did with jet ski engines?