morespeed

I have a 2001 496 horizon non HO freshwater only motor that has around 850 hours that is giving me fits maybe i'm just paranoid. I have had this boat since September 09. It is pumping about twice the amount of water out of the starboard exhaust compared to the port exhaust. Also at idle I checked the risers with an infrared temperature sensor and the starboard at idle with a warm engine is running at 105deg and the port is at 125deg. From what I found searching the internet riser temp should be between 120-130 not sure if that applies to my motor or not. I don't think the risers are to hot but the 20 degree difference between sides and the difference in water flow are what really concern me. All of this testing has been done on the hose I haven't had it in the lake yet this year. Here is a list of thing I have done for trouble shooting. First I went through all of the raw water lines looking for leaks. let me ad that I put in a brand new Hardin marine Water pump and impeller at the beginning of last year. next I removed the water pump to check for scoring or a bad impeller not expecting to find anything wrong and I didn't It was perfect. Next I did to much internet searching and found out about the aluminum manifolds and risers on early 496's and thought maybe my risers or exhaust manifolds are bad or worse leaking water into the cylinders so I pulled the port riser off inspected and borescoped my exhaust manifold everything was in great shape. So I move back to following the water lines I removed, back flushed, thoroughly cleaned and inspected the steering cooler, oil cooler, and coolant heat exchanger along with backflushing all of the lines along the way. Still the same problem so I read about a check ball at the bottom of the exhaust manifolds I started to remove this which is tight as hell so I decided to just crimp off the line it runs to which will give the same effect of blocking the line off to make sure water the ball isn't hung up and diverting the water flow back down instead of out of the engine. I am lost what to do next or maybe this is normal but I don't remember the big temp differences last year. any help or suggestions will be appreciated. Daniel

morespeed

Forgot to say Hi. I'm new around here i've been on the forum for awhile but this is my first post. and trust me I know how to search and I have done plenty of it but cant find the info i'm looking for. Daniel

vindicator101

Sounds like you know how much water it normally pumps so I'm not going to say there's definitely not a problem but I can say in general the stbd side will run a little cooler than the port side. On mine ('01 496 HO) if it's on the hose it has always pumped twice as much out the stbd then port. I even have to run the hose directly to the spicket and not through a hose real our I will loose suction. I never have a problem in the water though. I would check it while in the water. Just my .02.

morespeed

I plan on putting it the water next weekend to check it i'm thinking the hose might be some of the problem also.
Something interesting though a friend of mine has an '06 496 non HO so I went over yesterday to check his water flow and temps on the hose. his does the same thing as mine more water on the starboard than the port and same 20 degree difference between the risers starboard being cooler I find that really interesting seems like a poorly engineered raw water system. If this is always the case. I am curios to see what mine does in the water next weekend.
Thanks for the info on yours that lets me know its not just mine apparently they all do that.

paul buckner

Not 100% but i read some where on here that one side has to go one or more runs up and down in the heat exchanger than the other side .

Dave M

I noticed this issue more when running on the hose, not when the boat is in the water. My 496HO was like that and now my 525efi does the same thing. The port header gets pretty warm when running on the hose, but not when in the water.

morespeed

Thanks for the feedback. Sounds like my motor is normal I'm just being paranoid. I'm gonna take it out Saturday and bring the temperature gun with me. I will post. What kind of temps I get.

motor

iTrader: (3)

running on the hose doesn't count as far as water flow ...the pump will draw more water than hose can provide