Broken bellows sink boat

[marvinjansen]

I heard that a broken bellows can cause water to fill your boat, any truth to that? I have an older 1973 Aristocraft 19 with a Mercruiser 165 and want to try it out before I replace everything. Just at a local lake and not far from the dock and shore to start with. Don't want to sink on the first outing.
Also, how much trouble can I get in trying it out with the impeller of unknown age? I can watch a temp guage and not overheat the motor but don't want to have impeller parts plugging up holes where they are hard to get to. Anyone with any experience in a bad impeller or bellows?

 

[dingdongs]

Re: Broken bellows sink boat

if your boats trailerable you could always drop into the water without releasing from trailer.run boat up and raise and lower drive without putting in gear .if bellows r gone water will enter and if impeller is shot engine will boil.you want neither so for peace of mind only release from trailer when your sure.for peace of mind if you dont know when they were last done should be on agenda as things to do over the winter.

 

[GLENN M]

Re: Broken bellows sink boat

broken bellows can sink you pretty quick,possibly faster then you can paddle,cuz your motor over heated and head gasket went and motor hydro locked,make sure before you try be safe no second chances on water.

 

[6meter]

Re: Broken bellows sink boat

A ripped drive shaft bellow will put you at the bottom of the lake, if you just sit there. No water comes in while on plane.
Chances are that in your trial run, the impeller won't shred during that trip. Its either already gone. going or ok. Odds are with you.

 

[Don S]

Re: Broken bellows sink boat

I heard that a broken bellows can cause water to fill your boat, any truth to that?

This is one of those "But" questions.
Yes, a broken bellows can cause water to fill your boat.
BUT.................... if you have a working bilge pump with a float switch, even the smallest bilge pump will keep up with the minor flow of water from a bad ujoint bellows, It all comes in through a small 1/8" or less hole, usually filled with grease and muck. IF you don't have an automatic bilge pump, and you don't have enough sense to open your engine hatch and look once in a while, and you stay on the water for days while water starts coming in over the floorboard. Then yes you could sink your boat.
It will NOT be fast. Even with a shift cable bellows bad too, the chances of sinking a small boat is remote.

Of course if you have no float switch and you leave your boat in the water at the dock for weeks on end during the summer, then sure it could sink. But that would be your fault for not having an automatic pump.

 

[camaro_z28]

Re: Broken bellows sink boat

My bellows starting leaking this summer from dryrot. worst it ever did was kick the pump on about every 3 hrs for 30 seconds. It was docked full time this year after being trailered for 3 yrs. I'm sure it can get worse, but I dont think dryrot will sink a boat in any speedy fashion. (I did replace mine this fall after seeing that start to happen)

 

[marvinjansen]

Re: Broken bellows sink boat

Thanks for the great information. I think I will put it in for a trial run soon. No one expressed problems after an impeller came apart, so can I assume that the passages are open enough that they just pass thru and won't cause a problem? I changed one in a honda 5hp on my sailboat and after 30 minutes it overheated from previously broken blades, good thing I had sails too.

 

[wire2]

Re: Broken bellows sink boat

.... No one expressed problems after an impeller came apart, so can I assume that the passages are open enough that they just pass thru and won't cause a problem? ....

Maybe. If it has power steering, there will be a heat exchanger in the water supply hose just inside the transom. That has lots of small holes that *could* be plugged by impeller bits.

After that, they will end up in the thermostat housing, then possibly on to the block, heads, & exhaust manifolds/risers.

 

[Simoniz]

Re: Broken bellows sink boat

If the impellor is shot, the temperature gauge wont tell you until its too late. By the time the engine is showing hot on the gauge you will already have overheated the exhaust, possible damaging the rubber and plastic parts in it and the water pump.

If you must run the boat with a doubtful impellor, have someone keep a hand on the exhaust elbow and shut it down if it gets too hot to bear. An exhaust could run hotter than this and not damage anything but the hand comfort level will keep the exhaust safe and a good impellor and water pump will keep the exhaust temp quite cool.

 

[marvinjansen]

Re: Broken bellows sink boat

--------------------------------------------------------------------------------

"If the impellor is shot, the temperature gauge wont tell you until its too late"

I think I will put in an impeller and not have all this to worry about. I will try doing it on the boat like I have for my 18hp evinrude, it was easy. I sure appreciate the education I have received on this issue and hope to share a successful first launch.

 

[mr 88]

Re: Broken bellows sink boat

99% of the time the bellows is cracked on the bottom.They should be stored in the down position and most people do the opposite, main reason for them going in the northern climates. Raise the outdrive and slowly feel and probe for a tear. If the bellows is shot, your U joints and gimbal bearing are in need of replacing as well. As long as your that far the shift bellows might as well be replaced. Fire her up in the launch area and let it idle for 5 minutes or so and watch the temp gauge along with the motor for excessive heat rising from the head. If the gauge moves to the "middle" and stays there take her for a run and keep a close eye on the temp.If it rises slow down to a troll and see if it drops. If it does you may have a stuck thermostat or bad impeller.Pull thermo if that happens and see what the results are on your next run or better yet throw a new thermo in before to eliminate that source.

 

[Home Cookin']

Re: Broken bellows sink boat

use your past experience. install sails, just in case.

 

[dingdongs]

Re: Broken bellows sink boat

water temp guage does not measure hot air so best to run on muffs and either release a block drain and see if warm water is coming out or pull hose off briefly which comes from transom to thermostat housing to see if theres a flow from leg.no flow means impeller or blockage.

 

[Dick Sorensen]

Re: Broken bellows sink boat

Just for the piece of mind change the bellows and the impellor. Then you dont have anything to worry about....Mercruiser's recommendation is every three years on the bellows and every year on the impellor...I don't follow it but.......hope neither of us have to beach our boats to keep them afloat.

 

[marvinjansen]

Re: Broken bellows sink boat

I tried it on muffs and impeller didn't pump any water. hooked hose direct to motor and it ran great. now i have replaced impeller and put it on the water for a trial run and it ran great! Noise at rear of motor probable gimbal bearing so next is to replace all bellows, gimbal bearing, and check u joints. Looking for a great summer on the water.

 

[Bluepike]

Re: Broken bellows sink boat

This may answer your question about bellows. I went for a quick spin last September and everything looked fine at the docks. When I came back in an hour later, I found a boat sinking at it's dock. Called the marina office and they brought a pump and we saved the boat.

It had a bilge pump but didn't have a float switch. All that water came thru a hole in the shift bellows about an inch in diameter. Another hour and she'd have been under water.

That is a bait box you see floating between the seats

 

[dsiekman]

Re: Broken bellows sink boat

Yes, your impeller can come apart and will most likely be a PITA to get all the parts. A few years ago I suddenly started having overheating problems with my 7.4 merc. When I pulled the hoses at the tstat housing there was no water. The main circ pump was new and I had changed the impeller every spring since I had purchased the boat and had always removed intact impellers. After much cursing and disassembly I found that the previous owner or owner's mechanic had lost every vane off of an impeller and not gone looking for it. They were completely jambed up in my power steering cooler (or was it oil cooler?)...under the engine. Loads of fun, let me tell you.

 

[tschmidty]

Re: Broken bellows sink boat

Well he replaced the impeller so that's good. Glad the boat ran well for you. And while overheating is obviously bad, the problem is all those bits of impeller clogging passages after it disintegrates as the guy above states.

 

[marvinjansen]

Re: Broken bellows sink boat

when we replaced the impeller, the old one was 100% there, no broken off pieces, so that was good. it was stiff and even seemed warped on one vane probable from sitting for years. sure pumps good now. nice to feel the imput 5/8th hose cold and the big one to the engine warm.
I hope to replace the bellows, gimbal bearing, and check the u joints next. I ordered a Sierra 18-8205 kit and hope it's the right one.

 

[marvinjansen]

Re: Broken bellows sink boat

pulled the drive and the driveshaft bellows looks good to me. It had alot of gear oil in it and doesn't leak at the bottom for sure, no water it there. the shift bellows seems to be ok too, no leaks. The exhaust bellows is not leaking but has some small weather cracks showing. It looks like that bellows can be changed with the drive on, can it?