1987 Evinrude 90 hp overheat horn

[Champion88]

I have a friend that has a 1987 Evinrude 90 hp E90TLCUR. He had a problem with it overheating so we replaced the water pump, thermostats and the relief valves. It now seems to cool, but every once in a while his overheat alarm will go off (constant alarm, not intermittent), and it not consistant, it happens sometimes at full throttle, and sometimes at idle.
The water pump was complete when we replaced it, it hadn't come apart and plugged up the water passages.
Could this be caused by the temperature switch? or what else?

[1993392]

The constant beep can also indicate a fuoe restriction alarm. Does the motor go into SLOW mode where it won'
t reve over 3K ? If not it may not be an oerheat.

[Champion88]

No, it runs great, just makes the operator very nervous!

[ChampioNman]

May be worth the cost of a couple of head gaskets to check the H20 deflectors condition in the water passages inside the block.

[Champion88]

ChampionMan....I saw in another post that this could possibly be a fuel problem? We just recently removed the VRO and replaced it with a fuel pump from a 1973 85hp motor. It now runs a lot better than it did before, so I didn't think about it maybe being fuel related, especially since I didn't realize the steady alarm could mean a fuel starvation. Or does this apply to this 87' motor too?
He was only using the VRO as a fuel pump, he had plugged off the oil and started mixing the gas prior to that. The VRO pump was leaking very badly and they're quite pricey. My other friends motor (yes I have more than one friend) had the VRO replaced with the same old style fuel pump and his works great.

[Champion88]

I was just thinking....could it be that we unplugged the wires going to the VRO and now it thinks it's not getting enough fuel? Could we jumper the wires to make it think it's not starving for fuel?

[rudetech1]

I'm with ChampioNman on the water deflectors. Usually get weak after 10 years. Your engine also builds up crud under the water jacket covers on the cylinder heads that need to be cleaned out. I'm betting if you pull the heads you'll find the deflector have swollen into the passages cutting off the water flow. When you pull the heads and the jackets, put NEW temp switches in them. The new ones have ground leads that cut down on false warning alarms.

[ChampioNman]

The wires are for the no oil alarm, it's not an electric fuel pump so jumpering will not have any effect on fuel flow. Follow the small hose that is "t'd" off the main line running to the pump, at the end is the vacuum switch disconnect the brown wire (alarm) they rarely go bad but like Rusty says never say never. Check the deflectors first, and install the new temp switches like Rudetech says.

[Champion88]

We took it to the lake last weekend and ran it for about a 1/2 mile at 3/4 throttle and the steady buzzer alarm went off. So I unhooked the temperature switches, and when I turned the key back on the alarm still went off. It continued to do this until we sat there for about 20 minutes, and then we could turn the key on without the alarm going off. I hooked the temp switches back up and we ran it back to the ramp and then the steady buzzer went off again, but while he was letting me off at the dock the alarm quit buzzing.
I told my local mechanic about removing the VRO and he said that we needed to make sure we unhooked the oil alarm, that it would cause the steady buzzer if it's not disconnected.
This motor has a 3 pin plug that we unplugged from the VRO, should we jumper across some of the pins or ???
We have the heads off right now and don't see anything wrong with the deflectors, can you enlighten me as to what they should be doing. Should they seal off the area completely or still let part of the water pass by them or ???.
Thanks for any help you can give me.

[Champion88]

I just got back from looking at the deflectors. Looks like to me they are to prevent water from passing between the cylinders, but to still be able to go down that side undisturbed. Is that correct?
The three pin plug that I referenced earlier has a black, brown and blue (could be green) wires. Should I do something with this plug?

[ChampioNman]

They should be round and pliable. The VRO oil alarm should be disconnected from the alarm system. Try and disconnecting the Vacuum switch alarm and running it, See if you can borrow a temp gun and check the block temps should be less than 140*.

[SEAHORSE]

That 90hp does not have a vacuum switch for fuel restriction alarms, only the V6's do.

Mud, sand, or salt buildup in the cylinder head passages can restrict the outflow of water and cause high speed overheating. Also misplacing, pinching, or forgetting the water cup oring, or even blocking the bleed holes with sealer can cause high speed overheating.

What part number water pump kit did you use and were there any parts left over?

[Champion88]

Sorry, I've been out of town a few days.
We took the heads off and replaced the water deflectors, they were a little out of round. He took it to the lake and the alarm still goes off. We found out that it's the starboard side alarm that causing it to go off. I will borrow a temp gun on Monday so we can find out what the temp is. I have chased all the wiring for the oil sensors and they are all unhooked, so that can't be a problem.
The water jacket area in both of the cylinder heads was immaculately clean, not a speck of sand or anything. We didn't take off the covers on the heads, but I will if we find out the temp is too high on that side. I will update after I find out the results from the temp gun.
Thanks for all your help, we'll get this thing figured out yet!

[j archer]

I have that issue the first couple runs of the year and then does not do it for the rest of the fishing season. I was running mine in the drive yesterday and the buzzer went off I shut it off let it cool restarted let it run and did not go back off, any ideas on that?