Strange situation

[km1125]

Source of the post The boat is in salt water. The risers and manifolds were changed in 2018. The engines have 650 hours on them. What is confusing me is that both gages show the same temp. I would think that if there was a clogging issue it would be one engines not both at the same time and same temp.
I will be on the boat this weekend I will measure temps all around the engine.

When you wrote "both of my engines under load got up to 190 degrees", what does "under load" mean? Just at a slow cruise? A fast cruise" At high speed?

What about the heat exchangers and impellers? When were the heat exchangers last cleaned? When were the impellers changed?

It's not too surprising if they've both been operated in the same conditions for the same length of time that they would both experience the same issue, caused by some degraded condition. It's only when you have complete failure that you'd see one act different than the other (which also happens). The fact that both gauges show the same temp would be leading me away from it being a sender or gauge issue though.

[AlexB]

190 going 3500 rpm. When I slow down to 2000 rpm the temp goes to 180.
Impellers were changed same time as the risers in 2018 I am not sure about when the heat exchanger was cleaned. A friend recommended I check the strainers and make sure they are clean. After that do a barnacle buster cleanse.
What are your thoughts on this? Is it hard to do the cleanse?

[bud37]

Alex, is the boat in the water year round ? If so do you have diver at the marina where you are?

[AlexB]

No the boat is in the water from May to Nov.
I haven’t asked the marina if they have a diver.
But at low tide I can put in a mask and get to the raw water intake.
Do you recommend I do that?

[bud37]

Source of the post But at low tide I can put in a mask and get to the raw water intake.
Do you recommend I do that?

NO, You should NEVER swim in a marina......and just to add, IMO nobody should be diving under their boat unless they are trained and experienced.....dangerous place to be.... .....be safe ask your Marina about dive services.

So this spring was the boat hull and intakes clean with good bottom paint ?

Alex, a couple things, 4 years on impellers is pushing it, both engines being the same is telling, consider what buster posted and the rec from your friend about the barnacle buster. It is important to go thru these things methodically one thing at a time IMO.

Confirming your engine temps was a good first choice on your part......have a good look around.

[AlexB]

Point well taken about not swimming in the marina.
I will ask about the marina’s dive services.
I wasn’t there when they painted the bottom. I assume they cleaned it and the intakes.
This weekend I will try to check the health of the impellers. And if I can find new gages in store I will check those as well

[buster53]

I had my boat out for winter of 20/21. Splashed last spring with clean bottom and fresh paint. 10 weeks later, I had lost 7-8 mph on my top end. Did a short haul and my running gear was encrusted with a heavy coat of barnacles. I’ve never seen that much growth in that short amount of time. Bottom was still nice and clean. Either the boat yard did a piss poor job of painting or used crap paint on the running gear.
A suggestion for the future….after getting a fresh coat of bottom paint, take your boat on a quick cruise, run it up to wide open for a minute or so and take note of your top RPM’s and speed. Now you have a baseline to judge when you have a problem that needs addressing as I did after loosing 7-8 mph.

[buster53]

This weekend I will try to check the health of the impellers. And if I can find new gages in store I will check those as well

Make any progress this weekend?

[AlexB]

Not as much as I wanted to. The store didn’t carry any water temp gages so I ordered them, but I did use an IR gun. I measured all over the engine. The risers were at 115 at 2000 rpm. Not knowing exactly where to measure the temp I was taking readings all over the engine. The highest temp I found was 170 except for where the exhaust goes out there it was 217. But I figure that at the exhaust it should be hotter. Next step to change the temp senders and gages and I want take the boat out of the water and inspect the intakes.
Thoughts?

[AlexB]

Oh and I am not sure where the impellers are. If anyone can post a picture or a link that would be helpful.