DF140Z Running Hot

[Reel Poor]

The engine info (DF 140 Z 14002Z-110301) This engine was soft grounded last year and set of the temp light and rev limit light. Boat was towed to dock to keep from causing damage. Water pump kit was installed and engine showed no signs of problems thru the end of last season. Boat sits through winter on a trailer and when put back in water this year wants to overheat, temp and rev light came on, first trip. Checked and replace just impeller, the one removed showed no signs of problem. Water test and still have same over heat results. Took it to a certified Suzuki repair shop. They said they flushed the engine with lower unit off and thermostat out, replaced the water pump assembly, and thermostat(s). Engine still runs with same overheat results. I noticed today when at idle the tell-tail pisses but above 1500 stops pissing. Bring it back to idle and it starts pissing again. Why would it **** at idle and not above idle? Shop said all they could suggest at this point is to disassemble the power head and clean it because it must be clogged. Over 4000 rpm engine runs overheats fast, maybe a 1/4 mile. Below 3500 rpm and it will go several miles before overheating. If the engine was partially clogged would the tell tail act the way I described or would it possibly **** better at higher rpms and stop pissing at low rpm's? Any ideas? Thanks in advance.

 

[99yam40]

never heard of a pump stopping flowing at higher RPMs.

Something plugging TT under high flow conditions maybe.

how much mud.sand did you plow up when you grounded it?

I have had some luck with dropping lower unit, hooking up a water hose to pipe to power head with an air hose teed in also, pulling stats ,turning on water full blast and pulsing compressed air into the water flow off and on to help stir up the sand in lower parts of power head to try and get it flushed out.

 

[Reel Poor]

Can anyone explain how the water pressure valve works? I don't need to know it controls water pressure. If this valve is bypassing could this cause my loss of pressure at higher RPM? When it does bypass where would the excess water be dumped? Can this valve be tested?

 

[Sea Rider]

If that OB happens to have been used extensively on salt water definitely has tons of salt layers, crusts build up on all water passages. Doesn't matter if have been correctly flushed with fresh water inmediately after use and that's from personal experience. If have changed all electrical and mechanical components that monitors temp with no avail, that's your hidden problem.

Your last chance before tearing powerhead down as the dealer knowingly suggested is to run OB on a barrel for some time at neutral/idle while Saltaway Product does its homework as expected.

OB's that work in salt water will start to collect micro salt layes one on top of the other right out the box due to hundreds of continuous ON/OFF temp fluctuating cycles. Besides all water passages are non that smooth as to avoid or lessen salt layers building up on them.

Happy Boating

 

[clanton]

Clean the water pressure valve, valve dumps water in exhaust housing. Water pump housing sealing surface must be flat, check with straight edge, if no gasket use sealer.

 

[Reel Poor]

It was a blown head gasket.