Logo

Water impellor 30

rhays

Member
"I have an 89 bayliner w/ a 3.

"I have an 89 bayliner w/ a 3.0. Idle temp is 170, whether on the muffs or in the lake, when cruising on plane around 2800 rpm temp will fluctuate between 160 and 180. If i open it up to 4200 at WOT, the temp sometimes gets up to 200 - 220.. slowing down brings it back down to 180's. Knowing that either water is not getting in or out, I checked the water passages, manifold, etc for obstructions and found nothing. What I did find was interesting,, when I pulled the impellor, some of the impellor blades we not curved all the same way.... ie,, 6 were curved in the direction of rotation, and 3 or 4 had turned/ flipped the other way, spinning against the flow of water,,, has anyone ever heard of this? also the impellor cage was not round,,, it was more egg shaped,,, any ideas? A dealer put on this new impellor for me last year,,, but I figured with three bolts that it was easy to check and I reinstalled it with all of the blades curving the same way,,,, just not had time to test it yet...
thank you for any help or ideas...."
 
It diesels? You know the motor

It diesels? You know the motor can run sometimes backwards if not shut off in the correct manner. and the last time shut off it diesel?

When you were checking did you by chance check the flapper / shutter?
 
"'Dieseling' is someth

"'Dieseling' is something different. That is that the engine keeps on running, but without ignition from the spark plugs. This is normally caused by a mix of leaking carb and 'glowing' deposits that ignites the fuel.
Some wings in 'wrong' direction is not un-known and normally caused by the engine going backwards about 1/8 turn when shut off. One cyl is going up towards compression, no ignition, and the compression pressure forces the engine slightly backwards. As the cobras has the pump direct on the crankshaft extension, this may happen. If a fresh impeller, the wings will turn the correct way at next start. You may test this by installing the impeller with some wings the wrong way, then crank the engine with emergency stop not connected (no ignition) for about 5-10 sec, then check the impeller.
The impeller cage/housing should not be round, but oval/eccentric or the pump will not work!
As for engine temp, check the manifold temp. If that gets 'burning hot. You may have a capacity problem. If manifold stays reasonable 'cool', Your circulation pump might need replacement."
 
"thank you for your help. I

"thank you for your help. I have not yet checked the manifold temp when the temp rises... I will do that this weekend. The impeller is oval shaped, and I will check that also to see if it turns the blades back around properly as the engine turns over. the engine does not diesel at all, but it certainly makes sense about the 1/8 turn as it shuts off. I did check the flapper and it was missing,,,, oops... i guess i have been lucky so far with it not hydrolocking, is it hard to install? any ideas of price for this piece? when I took off the rubber boot between the manifold and the exhaust tube, there is nothing there, just two holes in the pipe where it appears to go. I did run a coat hanger down that pipe to the lower unit and it was clear.
thank you again for any help or suggestions...."
 
"But that doesn't mean the

"But that doesn't mean the flapper is not blocking the exhaust.

You should remove the entire drive to check, the flapper had to go somewhere and can, and will block the exhaust.

It's up to you if you want to replace the flapper.

Volvo doesn't recommend replacement. Merc i don't know.

"My opinion, should not be taken as a expert, opinion, and i will not be held responsible for you following my recommendation".

I do not recommend re-installing a flapper / shutter.

Here is volvo's bulletin:

http://boatfix.com/new2.htm"
 
"Thank you very much for your

"Thank you very much for your help. I disconnected the lower bellows and shined a flashlight through it as i rammed a coat hanger up and down through the exhaust tube and got nothing, but didn't think about an obstruction in the lower unit. I will pull that this weekend. good excuse to check the u-joints, etc,,, It is truly amazing how much you can learn on this site. I will also follow your advice to check the circulation pump... do I just pull it off and look at the blades? Also, do you think napa has a gasket for that? I try to buy most of my things off this site, but today is thurday and I will work on it this weekend.... thanks again for all the help that you guys give daily..... it really helps us weekend mechanics,,, ps I have had the boat for over a year and it didn't overheat last year,, may be good odds that it is stuck in the outdrive..."
 
Back
Top