Sheared Exhaust Cover Bolts, What To Do?

[great_white_fisherman]

In the process of fooling around with my motor to get at the water channels for inspection and cleaning, I sheared off 3 severely corroded bolts on the exhaust cover. I tried drilling one out gave up on that idea after breaking several bits and finally realizing I had drilled off center and at an angle! Useless now. So I'm going to have to leave them in.

I'm not looking for tips on getting them out. What I want to know is if I will be ok to do this. I figure the exhaust doesn't experience the stresses that the head does. It just directs the gasses down the lower unit and channels water under low pressure.

Will it be fine missing these 3 bolts? Should I plug the bolt holes somehow?

 

[F_R]

I will resist the temptation to say something. But to answer the direct question, it depends. Water leaking to the outside might be ok, but if it squirts internally to the exhaust ports, she's a goner.

 

[racerone]

A 2 HP or 300 HP motor ??

 

[Rook66]

I'm not looking for tips on getting them out.

I got a feeling you'll wished you had.

 

[Scott Danforth]

find someone to tig weld nuts to the remnants of the stainless bolts

 

[great_white_fisherman]

A 2 HP or 300 HP motor ??

It's an Evinrude 25 1994

 

[great_white_fisherman]

I will resist the temptation to say something. But to answer the direct question, it depends. Water leaking to the outside might be ok, but if it squirts internally to the exhaust ports, she's a goner.

Why do you say that? Isn't the exhaust force enough to keep it out of the cylinders and push it down with the exhaust? It doesn't create a suction to pull it into the cylinder

 

[racerone]

I would make a dummy exhaust plate out of 3/4" steel plate.-----Then put that in position to use as a drill guide.-----Easy fix !!

 

[great_white_fisherman]

I would make a dummy exhaust plate out of 3/4" steel plate.-----Then put that in position to use as a drill guide.-----Easy fix !!

I was just thinking of doing that actually. But with the exhaust cover. I also broke the cover in the process and have a new one on the way so I could use the old one as a guide.

The one that I did already is a lost cause. But the other 2 might be salvageable this way.

 

[great_white_fisherman]

What do yall think about drilling and tapping a new smaller bolt hole inside the original bolt?

 

[great_white_fisherman]

Gave that idea a shot. Seemed to be working pretty well till I pulled the cover off to check my progress only to find that it had started straight and ended up angled, AGAIN!! I give up. She'll either work or she won't....

 

[Chris1956]

A drill press will drill the hole straight, if the block is flat on the opposite side.

There are some jigs to center the drill in the bolt remnant. One way is to drill an 1/8" hole thru a piece of steel or aluminum rod larger than the bolt diameter.

Now, using the 1/8" hole as a guide, drill a hole the same size as the bolt remnant. Put that hole over the bolt and drill from the other size with a 1/8" drill. That should give you a perfectly centered, straight 1/8" hole in the bolt.

 

[F_R]

Why do you say that? Isn't the exhaust force enough to keep it out of the cylinders and push it down with the exhaust? It doesn't create a suction to pull it into the cylinder

Reminds me of the advice to never pee into the wind. Sorry, I couldn't resist. But seriously, I have seen many motors destroyed from water squirting into the exhaust ports. Yes, many. No, the exhaust pressure is not enough to keep it out. Besides, the exhaust only comes in pulses. How about the rest of the time, when the piston skirt is wiping up and down across the ports?

 

[Sea Rider]

Better take the powerhead or the full motor to a machine shop and have all 3 broken bolts proffesionally removed..

Happy Boating

 

[great_white_fisherman]

I'm looking into a machine shop. What do yall think of putting a bead of high temp silicone on the mating surfaces? I just need to keep the water out of the exhaust right? That should do it? In the event that the shop says they can't do it

 

[F_R]

I'm looking into a machine shop. What do yall think of putting a bead of high temp silicone on the mating surfaces? I just need to keep the water out of the exhaust right? That should do it? In the event that the shop says they can't do it

I have no opinion one way or the other, concerning the silicone, because I've never had to deal with it. See, my experience was in a dealer's shop where I had to guarantee my work, and do it right the first time. And that included drilling out a bazillion screws---a learned skill, as you found out.

 

[racerone]

I think GORILLA glue company makes a sealer that will take care of any leaks.-----Yes any drilling of these screws usually has the drill wandering to the side.----Have used EDM to remove broken screws in the machine shop / factory where I worked.

 

[great_white_fisherman]

The machine shop said they wouldn't be able to do it. So tomorrow it's do or die. I'm already looking into buying another motor, a Johnson 35. This one can serve as a parts motor