Riser Question

[Bucks45]

5.7 Mercruiser. Is it normal for one riser to be hotter than the other? Port side isn't hot at all and the stbrd side is warm, but not so hot that you can't hold your hand on it. I have a temp gun, but loaned it to a friend. I'm fighting an overheat at idle problem and grasping at anything now. When I did a google search I found a post where a guy said that he always had one riser hotter than the other on any mercruiser that he's owned. Does that sound right? I'm going to get my gun back tomorrow and check the temps. Any help is appreciated.

 

[floridaboater1]

Re: Riser Question

That is not right... both risers should be at same temp... when one riser is hotter than the outher it usually means it has a clog in it and needs to be replaced. When these risers go bad completly you have all kinds of problems. Like hydrolock the engine. I would replace them both at the same time.

 

[bruceb58]

Re: Riser Question

That is not right... both risers should be at same temp... .

Incorrect statement. One will always be hotter than the other....at least at idle.

 

[Bucks45]

Re: Riser Question

Incorrect statement. One will always be hotter than the other....at least at idle.

Bruce....should I pull it off and check it or not? Not sure if it makes any difference, but the hose coming off the t-stat housing on the hot side isn't as solid as the cooler side. I can tell it's getting water, but it's not as firm.

Thanks,
Aaron

 

[bruceb58]

Re: Riser Question

get an ir gun and measure the temps.

 

[Bucks45]

Re: Riser Question

get an ir gun and measure the temps.

Ok....I'll post them tomorrow night. Thanks.

 

[ENSIGN]

Re: Riser Question

They will never run at the same temp. If you can hold your hand on them don't worry.

 

[Bucks45]

Re: Riser Question

They will never run at the same temp. If you can hold your hand on them don't worry.

It ran for about 10 mins. and I was still able to keep my hand on it with no problem. Thanks.

 

[Jeepster04]

Re: Riser Question

On our 5.0 volvo, the port side is warmer than the starboard side on both of our engines. Starboard is always ~90F and the port is always around ~110F at idle. Never checked them while running it down the lake.

 

[FreeBeeTony]

Re: Riser Question

I believe an overheat problem @ idle is usually caused by a bad impeller........a clog will usually show up @ higher RPM's under a load.

When is the last time the impeller was changed?

 

[Bucks45]

Re: Riser Question

I believe an overheat problem @ idle is usually caused by a bad impeller........a clog will usually show up @ higher RPM's under a load.

When is the last time the impeller was changed?

The impeller and pump are new. I appreciate all the help. I gave up. I've been fighting this problem for well over a month. Finally dropped it off at the shop today. They said I'll have it no later than Wednesday. I'll let you guys know what the problem was. Thanks for the replies.