1996 175hp EFI Offshore warmer on starboard head?

[tal]

I was helping some friends today with a 1996 175hp EFI offshore. My observations were it took a while to get the water to come out from the tell tale. We figured this happened because the pisser line is plumbed in behind the thermostats, so it wouldn't **** until the stats opened. Decided to replace impeller for good measure.

Second, the starboard side head seemed warmer than port. Idling on the trailer at the lake and back at home on the muffs never threw an alarm so we checked the warm head with an IR temp gun. It was about 123F, but seemed warmer to the touch. Port head was comfortably cooler the whole time. I don't remember the number for that side of the head but it was definitely easier to touch than the starboard head. Pisser remained the same even with new waterpump.

Is it normal for this engine to run warmer on starboard side, at least while idling? I dug up an old post on a crossflow merc running warm on the starboard but I'm unsure of the exhaust system on this EFI engine. Thoughts?

 

[tal]

Re: 1996 175hp EFI Offshore warmer on starboard head?

The guy my friend bought the boat from said it was overheating underway. Due to broken parts in the shift lever we couldn't lake test it. Parts are in the mail to fix the shifter so we will test the engine under load pretty soon.

So here's what we got, starboard head warmer than the other at idle, slow wee wee, never overheated at idle. I know the temp I listed above is well under overheat zone but the fact that one side is warmer to the touch than the other is odd. Thinking this symptom might increase with load? Maybe not? Anyone here who can give guidance?

Does this Merc have water deflectors that rot away and block passages like the Johnson's? I had to replace those before on one of my old engines.

 

[sxmerc]

Re: 1996 175hp EFI Offshore warmer on starboard head?

Stbd head will feel warmer to the touch as it is higher than the port side. Water takes the path of least resistance, so the port head will get water to it first as it sits lower than the stbd side. You'll find that any V-4 or V-6 engine, regardless of manufacturer, will experience this same thing, especially if the thermostats are located at the top of the head. I wouldn't worry at all.

 

[tal]

Re: 1996 175hp EFI Offshore warmer on starboard head?

Thanks for replying. That sounds reassuring. The water pressure at idle is 9 psi, does this sound about right?

 

[sxmerc]

Re: 1996 175hp EFI Offshore warmer on starboard head?

At idle on a hose... I'd be satisfied with that.