New member broken ring club

[Goneflyin]

This fall I bought a used Maxum/bayliner listed with a bad motor to replace bowrider which is close to 40yrs old and a little tired and soggy. The old boat has a 90hp I-6 Mariner that I got new in 1985 and looks and runs like new. The Maxum has a 90hp(1992) force that broke a ring on the top cylinder, dealer told the owner $3500 to fix so he dumped the boat really cheap.
After I got the boat home I pulled the piston and ran a glaze breaker hone through the cylinder and except for a small nick by lower exhaust port that I can chamfer out the cylinder looks good.
One of my questions is did the rings on these motors have a tendency to break? I see no signs of detonation or lean condition, colors on the pistons look even and it doesn't look like it ingested anything. The ring or rings may have been broke for a while because there's a blowby stripe down the piston that probably took a little while to make. Next question is do the pieces usually go out the exhaust port? Only mark in cylinder is by the exhaust port, piston top and head are clean. The dealer had pulled the head so I don't know if he found anything. should I pull the exhaust plate? I fished around in the ports of all 3 cylinders with a magnet on a wire but found nothing.
Lastly (for this post anyway) I bought the boat with the intention of putting the Mariner on it and selling the Force, any opinions on which is the better performing motor, I've never been in a boat powered by a Force engine.


Thanks Bill

 

[CVX20SPRINT]

Re: New member broken ring club

I would mount the Mariner and sell the Force after you get it running.Force has never had a very good rep. and the Mariner is basically a gray colored Merc.

 

[Frank Acampora]

Re: New member broken ring club

Broken ring will usually blow out the exhaust port and down into the water. You will never find it so don't bother removing the exhaust cover.

If the engine has the triangular shaped cross section "semi-Keystone" top ring, yes, they did have a tendency to catch in the exhausrt ports and break--Especially the ones where the top of the ring was even with the top of the piston, allowing exhaust gas to get behind and expand the ring for a better seal. If you are flush with money, replace with WISCO pistons and rings--I never had a ring break on one of those.

 

[Dave K.]

Re: New member broken ring club

Hi Bill, Welcome to the Forum!

Read your post yesterday & glad Frank replied (one of the best here) I've had fantastic service from my '84, 85hp. Many, many folks here have had similar results too. Force are easy to work on & fairly cheap to maintain w/ respect to costs of other O/B's. Yes, they have a bad reputation but if you stick around & do a search, the "bad rap" doesn't hold up.

The fact that you bought the Mar/Merc new & have cared for it (I assume)will give you a good repower. However, if you decide to repair the '92, you may be surprised how well they run. No doubt you will get more $$ for your used Mariner than a used Force no matter how well it runs.

Good luck w/ your decision & keep us posted.

 

[Goneflyin]

Re: New member broken ring club

Thanks for the replies. Being flush with money isn't in the vocabulary, kids tuition bills have replaced the toy fund. The top ring (keystone style)is about an 1/8 inch below the top of the piston. I was thinking of a Wiesco in the top cylinder and cleaning up the pistons and fresh rings in the other two. Any idea how the weight compares between the Weisco and a stock piston?

When I get it back together in the spring I want to break it in and see how it goes, I'm still leaning toward the Mariner because I've taken care of it and the HP is prop rated, it's been a strong motor. I'm sure the Force would be a good motor, it went 17yrs before the ring broke. I read a good thread on how Bayliner/force get the bad reputation because they're entry level and people boats don't take care of them or see or listen to whats going on till it breaks.

Bill

 

[Frank Acampora]

Re: New member broken ring club

As far as I know, any replacement piston, any brand, oversized or standard, is balanced to original foctory weight. Thus they just install with no special balancing procedure necessary. I just happen to like Wiseco, but there is nothing wrong with Vertex or Sierra.