Engine running hot after changing impeller

[ScarletArrow]

Hoping @Jody_Seal‌ or someone can direct me...

 

Put 200 in the water for the first time this year yesterday... engine started running hot 200+*.

 

Checked the thermostat and impeller - obvious problem, Impeller was bad.

 

Local MC dealer who sold us the parts also sold us new thermo that was Indmar brand.

 

After changing both the impeller and thermostat, engine still ran at 175*, plus started making a "gurgling" sound.

 

At first we thought it was pieces of the old impeller, but after checking all the hoses, we found nothing.

 

After about 6 passes, the "service" and "check engine" lights would flash and the boat would seem to want to go into limp mode, even though the temp gauge was static at 175.

 

We put the old thermostat back on and the temperature dropped to 160*, but (another symptom) the heater doesn't seem to put out any hot air.

 

Theory is that the motor is sucking air from somewhere, most likely the strainer at the rear of the engine where the o-ring seems to not be giving a tight seal.

 

Anyone experience with this or have thoughts?

 

Thanks in advance.

[GOODESkier]

Sounds like the first thing I would check. I had a 200 do the same thing last year, the strainer outer was actually cracked. First place I would start checking.

[Jody_Seal]

Indmar: Did you pull the hose from the bottom of the transmission cooler? Debris and grawdew seem to build up on the intake side of the cooler. Was the old impeller in one piece? if not did you locate the errant pieces, or back flush the system? tighten and check all hose clamps and mating sections. other then that you might want to do a volume test on your raw water pump. or your circ pump may have failed.

[ScarletArrow]

Thanks guys. It was weird that the new Indmar part didn't work in the PCM engine... it was pretty much identical, but I don't think that is our main issue.

 

We pulled the majority of the hoses, can't say for sure we did the transmission cooler I was the one doing "research" on planetnautique.com from my iPhone while @SkiKolb‌ was doing the wrench turning.

 

Impeller was in one piece - the blades were just frayed.

 

I'll replace the strainer and keep you updated.

[dtm]

I had the same issue with mine. I checked the whole system for possible air leaks, then I reassembled all the O-Rings (one in the strainer, and four in the pump housing) with a plumbers' grease, and the issue went away.

[LeonL]

I kinda had a string of bad luck with strainer cup cracking in the threads. Check that. What was the temp rating on the Indmar thermostat?

[Jody_Seal]

Crap !

I forgot to mention one other thing: Check and make sure the impeller hub is not spinning inside the rubber impeller. seen a number of those fail a while back.

[ForrestGump]

I saw that twice in the last 6 months, too.

[ScarletArrow]

Quick update I thought Ballers might appreciate...

 

Went through all of the checks suggested above - o-rings, crack strainer cup, hoses, etc. - and couldn't find where we were sucking air.

 

Another symptom we were having was that the hoses on top of the engine block and heater hoses were not only not getting warm, but didn't seem to have any water running through them.

 

We knew for certain that water was coming in from the impeller, but it didn't seem to be going anywhere beyond the thermostat housing (even with the right t-stat).

 

Finally had to break down and take it to the dealer and it turns out the circulation pump has gone bad.

 

Apparently there is a recall on this part with PCM, so it should taken care of under warranty.

 

Thanks!