Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

[Rick Fernandez]

Anybody with some tips on what may be the cause of my temp getting too high at idle within 10 minutes sometimes, but when running it goes back down quick and runs like a champ! I'm thinking it might be a bad Thermostat or Waterpump going bad but not too sure...I'm an amatuer with boat motors and would appreciate all your help with some tips or what to do! Its a 1993 Sea Ray Bowrider, 24ft I/O V8 350 5.7 liter. We just did a tune up on it after we bought it used, the Boat had 490 hours on it and in great shape, kept in dry storage. WE changed the plugs, changed the oil, did some overall maintanance stuff, and engine runs nice when going, but this over heating at idle deal is puzzling me...please help!

Thanks, all help is greatly appreciated!

rick

 

[anthony115merc]

Re: Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

have you checked your impeller?

 

[fendersfender]

Re: Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

Probably needs an impeller....if your not sure when it was last changed...change it.......a service manual is a must if you plan on doing your own maintenance....good luck!!

 

[Don S]

Re: Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

Being as you have a 1993 model, its an Alpha I Gen II outdrive.
Between the upper and lower units of the drive is a raw water pump that pumps water to the engine for cooling. When the rubber impeller gets too old it will not pump much at low rpm but does ok at higher rpm. On the Gen II drives they should be replaced after 3 seasons.
There are parts in section 3B of the outdrive manual on changing the impellers. Starts on page 3B-14 to 17 for dissassembly, then on to 3B-75 for installation. Here is a link to that section.
http://www.boatfix.com/merc/Servmanl/14/14b3.pdf

Here is a link to the rest of the manual for future reference.
http://www.boatfix.com/merc/Servmanl/14/14cover.pdf

 

[Rick Fernandez]

Re: Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

thanks so much for the quick replies! I really appreciate all of you answering so fast! regarding changing the impellar: No, I have not changed the impellar yet and do not know when it was ever changed, but I will jump on that first and replace it. I'll check out the manual as instructed from you guys to replace it...hopefully thats all it is! I'll post a reply again later on to let you know how it went and if she is running cooler at idle, I'll work on it today. Thanks again, you all rule for the quick response!

Rick

 

[Rick Fernandez]

Re: Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

Thanks so much for the tip! I will follow instructions and let you know how it went later!
I really appreciate your help!

rick

 

[Rick Fernandez]

Re: Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

Need a little bit more of your expert advice again please....I bought the impeller replacement kit on monday and we finally took on the job today to take apart the lower and upper units to remover the old one...I can say it looked rough in there...corrosion, debris, etc...My question is the we realized the rubber water seal that goes over drive shaft and slips onto the housing has a few little rips/cracks around the edges, so we should replace it, do you agree??? also the impeller replcmt kit instructions says we need a special tool to put that rubber water seal back into place, is that true we need that special tool/water seal setting tool??? I'm hoping I can get the rubber gasket/gromet and tool tomorrow at marine max so I can get this baby back together again and give her a try to see if how the temp does at idel after replaced.
Please advise!!! All your help is greatly appreciated again!!!!

 

[Don S]

Re: Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

That special face seal setting tool for the face seal on the outside of the pump, actually comes in the Merc gasket/impeller kit. It just fits over the shaft and around the outside of the seal and the inside height of the tool is 5/16"

 

[Rick Fernandez]

Re: Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

You rule for replying so quick...Thanks! The kit I bought was only the Merc impeller replacement kit, that included the impeller, two gaskets for the plate and housing, two round orange rubber gaskets/seals(seems like it would fit somewhere on the shaft itself), and two smaller yellow ones that the marine parts guys said i would probably not need. It wasn't the kit that included the housing unit itself, only impeller and gaskets. Maybe that other kit would have had the water driveshaft seal and tool included??? Not sure either what way the impeller blades should face/bend once I get housing over it when ready...Please advise! Thanks again bud!

 

[Don S]

Re: Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

Is that an OEM Mercruiser or Quicksilver kit? If so, what is the part number.
The kit I am used to seeing also includes the gaskets and seals you mention (those yellow ones are for the drain and vent plugs, and need replaced always) along with the SS plate that goes under the pump and the face seal.

 

[Rick Fernandez]

Re: Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

Sorry for the delay, had to go out to check the box,, it was the quicksilver impeller replacement kit..part number 47-43026Q06

 

[Don S]

Re: Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

Basically, I'll check that PN tomorrow cause it looks like an outboard motor water pump kit by the part number.

You could also go to your dealer and get a seal kit PN 26-816575A2
It's the face seal, the special tool, and instructions. about 8 bucks.

 

[Rick Fernandez]

Re: Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

thanks for the help Don S...that sucks if I they gave me the wrong part...but I'll just have to return if so, they were not a dealer. I was going to a mercruiser/searay dealer in the early am anyway to see if they had the tool and another part, closer to home too. I bought the part at the other place cause I was shopping for boat covers and they had the part there, so I thought it was correct part...Please let me know what you find out, I highly appreciate all your help! thanks again!

 

[Rick Fernandez]

Re: Temperature getting hot at idle...5.7 Mercruiser I/O Alpha One 1993..help please!

Don,
Thanks for replying to me late thursday night, all your help has been greatly appreciated. I went to the dealer to get that water seal for the driveshaft, and the package came with the special tool to place it on properly... I put the new impeller, cleaned up the old housing and put all the new seals, gaskets in place, slapped the lower and upper unit together yesteryday preped to take out today and test! I just the call from my brother in law that is testing it now in the water...says its running like a CHAMP! Idle temp and running temp is much lower than it was before, looks perfect(staying between 130-140....sweet! Unfortunately I'm working today and can't enjoy until tomorrow...but just glad she is running smooth and it was the impeller issue!!! Many thanks to you and the others as well for your expert advice! I really look forward to continue using this site for help, kindness and expert advice! Thanks again!