1990 Evinrude 200hp Water Flow Enough? Overheating Alarm

[bmx9854]

Jumping straight to the details...

1990 Evinrude 200 hp EX200TXESM

Bought the boat early spring 2017 – installed new WP accidentally ran dry for 30-45 second

Boat in water 2017 – used 4x’s progressively got high temp alarm sooner and sooner with each trip only under load if i recall correctly, weak telltale stream degraded with each trip

Spring 2018 (now) – Preparing boat and ran engine in bucket. Medium flow from telltale. Took off T stat covers and took out T stats and ran engine. Flow seemed OK. Video showing the flow below.

Checked head and water temps – using infrared thermometer head temps ranged 140-160F running at idle for 5-10 minutes. Telltale water was 130F. Water pressure at idle is 2-4 psi and rise to about 12 psi when throttled. PSI gauge was tested and reads accurately.

Does this look like enough flow through the engine? What are healthy psi (idle and at RPM) and engine temps for this motor?

I don't think there is anything plainly indicating the impeller is the culprit but I'll likely replace it anyway.

 

[211libwtfo]

You may have sucked up Sand/mud and have water jackets plugged or low flow. Can you try to back flush it

 

[Faztbullet]

Is the water control valve still hooked to throttle linkage? It has to be in place for t-stat/popoffs to work correctly/

 

[bmx9854]

Faztbullet - are you talking about the 3way diverted valve on the side of the engine? If so,yes I checked that valve and flow out its telltale line adjusts between idle and under throttle. I understand this valve relieves some pressure to allow more cooling water flow through the engine at RPM.

any idea if the actual water flow in the video looks adequate? And are my idle temps high?

 

[Faztbullet]

Temps are about right for idle as these run with little water thru them @idle. If its overheating at WOT check the t-stat inside the poppet and replace the t-stat diaphragm's. I would also check that impeller anyway.

 

[bmx9854]

Thanks for the response. I Failed to mention T stats were replaced last year too. About 30hrs on WP and t stats, I think they were sierra parts. I heated up some water (without a thermometer) and did see the t stats open. Based on the idling in the yard I'd guess they open at 140-150F?

 

[bmx9854]

Replaced the water pump with a new kit. The old one did look OK and the flow with the new install looks to be about the same.

I put the boat in the water for testing. Had 2-3 psi at idle for water pressure and about 8-10 psi under full throttle. The temperature coming out of the tell tale varied wildly sometimes luke warm from driving at ~2500rpm for 10 mins to untouchable at load and at idle speed. When I was running at ~4.5k RPM for 2-3 mins I got the constant alarm again. Cut back the throttle to idle speed and after a minute or two at idle the alarm ceased. I idled back to my slip but did try to open it up on last spurt before tying up and encountered another new problem. The boat would not go over 3k RPM and acted as if it had a limiter set at that RPM. I took a video which can be viewed below.

I started reading more in the SELOC manual and it describes, in addition to a high temp constant alarm, a constant alarm condition for a fuel restriction. Since I replaced the water pump twice in the last 12 hrs of use and the thermostats as well I'm starting to veer away from water flow problems and suspect fuel related issues.

Can any one reconfirm all my water pressures seems OK?

Would this motor go into a limp mode after a high temp or fuel restriction alarm? Not sure what the violent 3k RPM limiting could be connected to.

 

[crazy charlie]

I would take a ride with tststs out to rule that out as an issue.

 

[bmx9854]

Spoke with a few outboard mechanics and they suggest that the head passages are clogged with salt and/or a head gasket leak which makes sense since I have good water flow through the valley and out of the T stat holes and the fact that the water pump is new and the T stats opened when tested on the stove. Going to get the heads pulled off soon for inspection/cleaning and fresh reassembly.

 

[Charles_Riley]

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