Impeller Replacement Not Working 03 196

[shea.95]

I replaced the impeller on my 2003 Nautique 196. It is a 5.7L Excalibur 330 V-belt. After replacing the impeller the boat is not pulling water in. The engine is over heating. I am wondering if anyone has had this issue and what the solution may be. The impeller is brand new and the belts are all on correctly. Is it a hose sealing issue? Or could it be something else?

[NautiqueJeff]

Thru-hull valve open?

Where did the impeller come from? What part number did you order?

Could be an air leak at the strainer or a hose, but at least some water should get through if that was the case.

[functionoverfashion]

Is the pump on the right way? I changed an impeller on my '03 with v-belts today and it looked like it would be very easy to put the pump on the wrong way.

[shea.95]

I did not change anything hose wise or with the valves. I had my Nautique dealer match the impeller that I removed. It seems that a very minimal amount of water is getting through maybe as the drain hose will let some water out when opened.

What pump are you talking about? the metal parts are on correctly. Does the impeller need to be put in a certain way?

[AdamJBarn]

Could be sucking air. Take the housing apart and put a small bead of silicone between the 2 parts. That should help.


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[Infinity]

New impeller should have come with a new o-ring, its important that you get a good seal since if it sucks air, it may not work properly and will do exactly what you are suggesting, which is to suck a little water, but not enough to full prime and keep system from overheating. Occasionally, an impeller can also "spin the hub"....so even if new impeller, it could be faulty (rarer but certainly possible), I would take it apart and double check everything. Yes, its put in a certain way....when you install it you should make sure the "vanes" are going in same direction as when it came out (creates seal when they are all same direction)....easiest way is to put plenty of dawn dish soap on impeller and rotate it as you insert into housing, rotating in direction to get the vanes facing the direction you want them to go. Again, may sure that o-ring for the cover plate is placed properly and tightened down well (I remove my entire housing to ensure its all together right without being scrunched into engine while trying to do it).

[NautiqueJeff]

The impeller will flip the vanes around when the engine is started if it is installed with the vanes going the wrong way. That's not a big deal.

How many hours are on the boat?

I have seen raw water pumps so worn inside that they won't prime, but that usually only happens on high-hour engines.

My guess is either you have the wrong impeller or it has spun free from the hub.

Was the engine running hot before the impeller change?

Are you on Lake Norman? If so, I might be able to swing by and take a look at it for you if you like.

[JayG80]

Same thing happened to my buddy and his 02 196. Last month he replaced his impeller and had the same issue you described. I told him to use a nut driver to tighten all the hose clamps on the cooling system and clean a tighten the strainer bowl. No improvement.

Told him to put old impeller back in. Problem solved! The new impeller was bad and the rubber was spinning around the metal hub. I’ve heard there is a bad batch of impellers on the market.

[shea.95]

Got the problem fixed. Thanks for all the tips! Ended up getting new bolts for the housing and also using gasket sealant and the system is working well now.

[shea.95]

So the impeller is working. However, now when the boat is going for awhile the boat loses power and slows to an idle, then will speed up again and die again and so forth. There is no abnormal engine noise or anything. While, there are no squealing belts, the belts do seem loose. I am wondering if this could be the issue. If it is, how do I ensure the belts are tight enough on a v-belt without an auto-tensioner? I am unsure how to pull the pulley's tight enough so the belts are tight.

[JayG80]

You should check the fuel pressures with a gauge attached to the schraeder valve on top of the FCC. Check Key On/ Engine Off. Check at Idle and then at Hi RPM. The proper pressures are noted on the plastic engine cowling. I have the Ford engine so I don't know the GM specs. I think they are higher than the Ford's.

As far as belts. Push down ont he upper strand of the belt at a point midway between the alternator pulley and the circulating water pump pulley. Belt should deflect 1/4". If it depresses more than 1/4" adjust the tension by loosening the alternator bolts and tensioning to obtain the correct tension.

[Skidave]

Sounds like a fuel issue. That has nothing to do with your water pump or belts. Unless you Are overheating and the check engine light turns on.

I Have the same vintage motor. I just replaced the low pressure fuel pump, high pressure pump, filters ,etc.

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