Bellow Problems

Bellow Problems May 12, 2015

By Stephen Horsfall


We have a Mercruiser Alpha-1 which had the exhaust bellows come off while the drive was tilted up and caused our boat to sink.  We want to know how many of the bellows should be replaced to make sure that this does not occur again.

Rob & Selene, via e-mail


The usual problem with sinking with the drive up is the shift cable bellows or the U-joint bellows, often because they are chewed by muskrats.  A hole in the exhaust bellows will not cause a boat to sink.  Muskrats can also chew through the oil line going to the drive oil level reservoir and cause water to get in the oil of the stern drive causing drive gear and bearing failure, but this is not very common.

So two bellows need to be replaced, but normally all three are done at the same time.  Muskrats can also chew through the water inlet hose in this area, though this will not cause the boat to sink, it can lead to engine overheating as the hole will allow a drop in cooling flow from the drive to the engine.  All the rubber exterior components of the stern drive should be inspected at least once a year for damage and flexibility and should be replaced as a precaution at least every five years.


I am thinking of making an offer to purchase a 1997 Chaparral Signature 240 with some 340 hours on it.  The boat is in good shape and I have not run it in the water yet but have listened to the 350 Mag efi Mercruiser engine and it sounds good.

The owner states this summer he hit something and insurance paid for for a  new outdrive.  I noticed after a cleaning (it is out of the water now) that the drive says Bravo One, but the lower unit is a dual prop unit.  Could it be that the mechanic mismatched the upper and lower drive units?  Is this drive too small for the engine and the weight of the boat?

Name Withheld By Request, via email


I would not think the durability of the upper case would be a problem running the dual prop lower unit. If you are thinking of completing the sale before spring launch, I would definitely recommend having a qualified marine surveyor do a complete inspection of the boat and all its equipment prior to completing the sale.


Well done Mr. Horsfall.  I am a 50 year old boating enthusiast with an ETEC 300.  I am also a family doctor and daily see people with damaged hearing.     

I have taken to wearing earplugs on my boat and recommending them to my passengers.  I carry a pack of those cheap disposables but have a custom made set for myself.  They sure make a difference, even in the amount of fatigue at the end of the day.

I think you have hit on an important issue; many of our “toys” are damaging our hearing.  Why not follow-up with some recommendations by an audiologist?  May is Speech and Hearing month and would be a good time to reach all of us in your column as we head back out on the water.  I’m sure a certified Canadian Speech Language Pathologist and Audiologist could be found in your area that would help with a column or I could suggest my local contact.  It would be a useful public service and timely.  

J. Stephenson, via e-mail


Thanks for the nice email!  Always a pleasure to know I am being heard.

I have a very fine audiologist who is a contact here at the Civic Hospital in Ottawa who I can consult with, and I will do a follow up for all our readers.  I have good experiences with the people at the Civic and with Dr. Shramm as I have been fitted with a cochlear implant about five years ago and I recently went in to have the defective implant replaced.