2 stroke 115hp thermostat housing bolt snapped

[davehank]

Hi guys,
I posted here once before with an electrical problem, got it fixed pretty quick. Was hoping for some more advice. I have a 1993 2-stroke 115HP v4. I just snapped one of the bolts on the thermostat housing. I won't fix it myself, I'll get a shop to do a decent job. My question is, the weather's looking real good tomorrow, do you reckon it'd be safe to use it for a short trip, about 5km total? I don't want to risk doing serious damage, but the head has 14 bolts, 7 on top cylinder 7 on bottom, one bolt missing from the top seems like it could be OK. It's the bolt next to the temp sensor.
Thanks
Dave

[davehank]

No, it doesn't look like it's leaking. I have a back up little engine that can get me home if the big engine overheats. My worry is that water could get into the cylinder and blow it up.

[TownsendsFJR1300]

No, it doesn't look like it's leaking. I have a back up little engine that can get me home if the big engine overheats. My worry is that water could get into the cylinder and blow it up.

Water won't get into any cylinders should that housing leak.

It'd just leak to the outside of the engine block.

IDK if anything electrical is under it. If so, perhaps some duct tape to keep any water intrusion from occurring.

You should be good, just keep an eye on it.

Weather and water conditions permitting, perhaps run with the cowl off so you can keep an eye on it.
(probably overkill actually)

[davehank]

That's good thanks. There's no electrics under it so it should be ok. I thought the housing was part of the cylinder head but it's only a cover. Fishing trip back on

[TownsendsFJR1300]

Yep, the thermostat just sits there, usually with a rubber gasket around it(up against the block).

There's no springs pushing that cover off, the cover just seals up the block / cooling system..

[rodbolt17]

why not simlply fix the dang thing BEFORE you blow it up?
sometimes the cowl drains wont drain faster than a water leak.
when that happens it tends to suck water into the intake.
bad things happen shortly thereafter.

[pstephens46]

why not simlply fix the dang thing BEFORE you blow it up?
sometimes the cowl drains wont drain faster than a water leak.
when that happens it tends to suck water into the intake.
bad things happen shortly thereafter.

He ain't got no bullet point drill bits.

[rodbolt17]

home depot.
lowes.
Ace.
you can drill it and tap it for 1/4x20 or 6x1mm.
but as the flywheel moves a lot of air and turns water into a mist then the intake sucks it down.

not the first snapped rod I ever saw due to the water leak was faster than the cowl drains.

not the first piston failure I ever saw from water mist.

Yamaha has several tech bullitens about it.

[davehank]

So I put the boat in the water and it started leaking more than I liked so I cancelled the trip. Going to have a go at getting the bolt out. Do you recommend drilling it out, or use an EZ out to extract it? I read a couple of threads where the guy broke off the EZ out in the bolt. If I drill out the bolt, do I do it in one, or start with a small bit and work up?

[TownsendsFJR1300]

If the boats on a trailer and your not comfy with it, a machine shop can take that out without a problem, maybe $30.00...

[davehank]

I found a thread where rodbolt17 and boscoe99 said never use easy outs, so I got my answer about that.
I just started taking the cylinder head cover off, the engine's 24 years old and I'm pretty sure it's the first time it's been done. I was avoiding it because I thought I'd snap a few more bolts but they all came loose pretty easy, I was a lot more careful this time.
Best way to drill out a bolt? Thanks

[davehank]

If the boats on a trailer and your not comfy with it, a machine shop can take that out without a problem, maybe $30.00...

Yeah, I'm off down the hardware store now, will see what the options are. If I'm not totally happy then I'll use a machine shop. Was thinking it could be a useful skill to learn in case I break any more bolts.

[ausnoelm]

It's not that difficult, just take your time, start on centre, drill straight, start with a small drill and work up.

[davehank]

That went well. I started drilling off center so the bigger drill size started cutting into the head. That didn't look good, so I decided to ignore everyone's advice and try an easy out. After 30 minutes messing around with that... I broke it off in the bolt! Live and learn I guess. I'll check with a machine shop if they can do anything, otherwise I guess it'll be a new head.

[TownsendsFJR1300]

That went well. I started drilling off center so the bigger drill size started cutting into the head. That didn't look good, so I decided to ignore everyone's advice and try an easy out. After 30 minutes messing around with that... I broke it off in the bolt! Live and learn I guess. I'll check with a machine shop if they can do anything, otherwise I guess it'll be a new head.

With stuck bolts and stuck "Easy Outs", you have to know when to stop LEANING on it and go to plan "B"..

For bolts, maybe heat, penetrating oil, etc.

For drilling the broke bolt (too late now I know), but if you can't get a good center (with a punch), I'd grind it flat so you can find/keep center and punch/drill..

If there's any stud sticking out, I'd simply plug weld a nut to the stud. Between the heat and now you have something to grab onto, it usually zips right out..

A machinist has tools that can fix with what you have now..

BTW, you won't need a new head. Even if threads got buggered up some, a Heli Coil installed (which requires drilling the old hole slightly larger) works great and is stronger than the original aluminum threads.