8v92's turbo overheat at open throttle, help

[Thanasi]

both motors overheat at the same rate as i open up the throttles. I can run all day at 1200 1400 RPS and they are fine. Diver says the intakes are clean, does have new water pumps. I cannot find a single mechanic in southwest florida that will answer the phone let alone come look at it. What should i be looking at? any suggestions? should i start with the thermostats or the heat exchangers. what else? thank you

[Captain Ralph]

Keep it simple. It's usually a simple issue.
8V92 TI or TA?
Can the diver look up into the pickup and insure the path past the skin fitting is clear?
Barnacles do live in hoses and plumbing.
Do you have a clutch oil cooler before the sea water goes to the engines heat ex changer?
New issue or been creeping up? Been in shallow water lately?

[SKYCHENEY]

When did you last clean heat exchangers or change thermostats?

[barkdee]

Pull a downstream plate from one of the heat exchangers and take a look. Probably calcified-up. Happened to my 8v92s this summer. I thought they were clean; not. Had same symptoms you're having.

[cww]

You ain’t kidding about how difficult it is to get any work done on a boat right now. Everybody either won’t answer the phone or the ones that do are booked 6 months out. It’s nuts.

[JuiceClark]

both motors overheat at the same rate as i open up the throttles. I can run all day at 1200 1400 RPS and they are fine. Diver says the intakes are clean, does have new water pumps. I cannot find a single mechanic in southwest florida that will answer the phone let alone come look at it. What should i be looking at? any suggestions? should i start with the thermostats or the heat exchangers. what else? thank you

Must be some little buggers growing just inside the intakes. They love the hot soup water this time of year.

I've wasted 4 months waiting on mechanics and to get the boat pulled. Mechanics I've sent biz to in leaner times don't bother to show. My friend at MarineMax wouldn't commit to a day to pull her. Frustrating.

I happened to call Diversified Yacht Serv in Ft Myers Beach. The guy set a hard appt. to have the boat pulled in early Nov. and and set another for a mechanic to come this week. Then, he sent a new diver who's great. In a few weeks, I'll finally be able to get a proper survey and tell Geico to give me a competitive rate or get lost.

[dottieshusband]

Check the intake strainer, check the raw water impeller, (I had to replace a backplate on a raw water pump even though the impeller was good), remove the intake side of the heat exchanger and look for old impeller pieces. Acid clean the heat exchanger, replace the coolant. Put in New thermostats, that ought to cover it!

[Thanasi]

thank you all for the replies, the problem just started one day, i will send diver down again, I have not had the heat exchangers cleaned for a while now. How many t-stats per engine? its a 1988 8v92 turbos

[dottieshusband]

Had a similar issue, slight overheat at full power. I checked all the usual suspects and cleaned the HE, yet it persisted. Exhaust water flow looked good, but hard to judge. I noticed backplate wear changing the raw water impeller. Changing the backplate fixed the issue.

[SKYCHENEY]

One day, I just had a thermostat start sticking halfway open. Things like that happen. If you haven't changed them in a while, now might be a good time to try that. I didn't know that was the issue until I put them in a pan of hot water and watched as one failed to open fully.