Inboard 351W cooling issues??

[OH Boater]

I have a 1989 Ski Challenger with 351 Windsor inboard and a Sherwood crank mount pump. At low speeds the motor will heat up to 180-200. As soon as I give it gas the temps immediately come back down to 140-150. I know don't go slow then right? lol. This is the speed I tow the tube and skiers at and drive through no wake zones so it is kind of unavoidable. Motor doesn't overheat and I am sure its not hurting anything at those temps but I am wondering if it is normal or not.

So far I have looked over the cooling system very well for any leaks. I checked the rubber impeller in the sherwood pump and it is in good shape without any visible damage or issues. I actually have the boat our and apart right now looking for leaks as an exhaust pipe was cracked and the boat almost sank in the dock slip after the bilge ran the battery dead.

If this isn't normal what should I start looking at?
Thanks

 

[Bondo]

Re: Inboard 351W cooling issues??

I have a 1989 Ski Challenger with 351 Windsor inboard and a Sherwood crank mount pump. At low speeds the motor will heat up to 180-200. As soon as I give it gas the temps immediately come back down to 140-150. I know don't go slow then right? lol. This is the speed I tow the tube and skiers at and drive through no wake zones so it is kind of unavoidable. Motor doesn't overheat and I am sure its not hurting anything at those temps but I am wondering if it is normal or not.

So far I have looked over the cooling system very well for any leaks. I checked the rubber impeller in the sherwood pump and it is in good shape without any visible damage or issues. I actually have the boat our and apart right now looking for leaks as an exhaust pipe was cracked and the boat almost sank in the dock slip after the bilge ran the battery dead.

If this isn't normal what should I start looking at?
Thanks

Ayuh,.... Welcome Aboard,.... Change the impeller, insteada just lookin' at it....

 

[Don S]

Re: Inboard 351W cooling issues??

When you looked at your impeller, did all the vanes straighten out while you had it out? They should have. If they don't, then they don't pump much water at idle. At faster speed, you get more water flow.
Impellers are a normal maintenance item and should be replaced every couple of years.

 

[OH Boater]

Re: Inboard 351W cooling issues??

Thanks and I think I actually solved the problem with your help in another thread Don, which ironically was about an 89 SKi Challenger.

The impeller that is in there is in good shape but I believe it is the wrong impeller and the previous owner has been running it like that for at least the last two impeller swaps. I have the old broken one along with the box from the one they put in and they are both 1 3/4 wide Jabsco and I believe this pump uses 2" wide impeller in this pump. In the photos in the other thread the guy also had the wrong impeller and it wasnt fitting flush with the pump cover and you pointed it out Don. This may be why it is hot at low speeds.

So I ordered the correct Sherwood pump impeller and hopefully it will fix the problem. Funny thing is I had the Marina ordered me a replacement and I got the same Jabsco impeller they had in the boat already

Here are a few pics of my boats. I just got the Bayliner. It has 200 hrs and I bought it off the original owner that is a friend of mine. Nice boat but hasnt been in the water in 7 years and now I am fixing all the little stuff on it.

This is my 57 Chris Craft which should be done this August. It will have a 283 CC inboard that I am currently rebuilding.

 

[Ned L]

Re: Inboard 351W cooling issues??

Very nice '57 Chris!