oops! just purchased boat w/bad motor!

[giannini7]

Hi to all! Just purchased 18 tiderunner (built in gig harbor, wa), with 78 115 johnson that had a dead hole. Did a compression test and #1 cylinder was 0 compression. Then made the fateful decision to pull head! I broke two head bolts during the process and was hoping to get some tips on how to procede from here. Besides using it as an anchor! Any help would be appreciated!

 

[1946Zephyr]

Re: oops! just purchased boat w/bad motor!

A dead hole means you may have a bad reed valve. No biggie. Don't worry I don't think you're in too much danger with this motor. It sounds like it may have seen some salt water, if you broke a couple head bolts though.

 

[giannini7]

Re: oops! just purchased boat w/bad motor!

thanks! hoping to get some info on removing broken head bolts!

 

[domwebhost]

Re: oops! just purchased boat w/bad motor!

Well, depending on how tight they are in you can go and buy a "Grabit" to try and remove it or if it won;t come out don't worry, just be patient and get urself a couple drill bits and a tap set to the thread size and shaft side and before you know it you will have new, shiny threaded holes. Then just get replacement bolts

 

[tx1961whaler]

Re: oops! just purchased boat w/bad motor!

How to get the head bolts out kind of depends on how much, if any, of the bolt is sticking out of the block. If enough is sticking out to get a pair of vice grips on it, then I'd do a couple of things: spray down in bolt and hole with a penetrating oil like PB Blaster and let soak for a couple of hours, the try the vice grips. Heating up the bolt with a torch can help.
If it is broken off at the block, then it will have to be drilled out. Don't use an EZ out for this. If it breaks off, then it makes it very hard to do anything else.
The reed valves have nothing to do with cylinder compression, by the way.

 

[a70eliminator]

Re: oops! just purchased boat w/bad motor!

Did you check to make sure the piston is moving because if it aint your wasting your time.

 

[giannini7]

Re: oops! just purchased boat w/bad motor!

ok! so the bolt is broken off at the bottom of the head, ie cant get head off! there are threads at the base of the head, already checked that! And I do believe the piston is moving, i can turn the flywheel by hand and watch the piston move!

Anyone no if these head bolts are hardened?

THanks and Happy Boating!

 

[kenmyfam]

Re: oops! just purchased boat w/bad motor!

Did you check to make sure the piston is moving because if it aint your wasting your time.

I imagine it is if a compression test was done.

 

[a70eliminator]

Re: oops! just purchased boat w/bad motor!

I imagined a broken rod cap with a compression reading of zero, it can happen and it would be the first thing I would look at.
Anyhow we now know thats not the case here and the broken head bolts are priority at this point.

 

[splitshot]

Re: oops! just purchased boat w/bad motor!

there aint but one way to find out...an old 115 i was working on had 0 on a cylinder and it was missing a complete ring , the weird thing was it didnt beat the head up or the piston top...i guess it shot it out of the exhaust maybe you will be this lucky

 

[crxess]

Re: oops! just purchased boat w/bad motor!

Soak it in PB Blast and try to remove the head. You have to be looking at deposits, not threads. The head could not be properly torqued if it had threaded holes.

 

[Benny1963]

Re: oops! just purchased boat w/bad motor!

if there broke flush ,they are hard but can be drilled. use center punch
punch dead center start with samll bit and work your way up till ya get to the size under the actual bolt size .then chase threads or retap worse case senario is that you drill up to helicoil size and helicoil ,broke 12 bolts on a saltwater 150 i just did stay away from bolt removers ,and take you time dont break a bit when useing the step up method .if ya can grab it liitle heat will help ,theres also sending it to the shop if ya get the right guy .
i use my automotive machinist he redrills and helicoils for 20 a bolt not cheap but not a bad way to go if ya only got a couple .

 

[crb478]

Re: oops! just purchased boat w/bad motor!

penetrating oil, heat, and left handed drill bits are probably your best bets.

 

[tmcalavy]

Re: oops! just purchased boat w/bad motor!

Or you could pull the spent powerhead and replace it with a known, good used one. Then work on rebuilding the old one when you have time, sell it for parts, or use it as a boat anchor.

 

[giannini7]

Re: oops! just purchased boat w/bad motor!

Thanks to everyone for the tips! I will try the penetrating oil and the heat!

What an awesome forum!

HaPPY Boating!

 

[jonesg]

Re: oops! just purchased boat w/bad motor!

if you visit some machinist websites they'll show you tips they use, one is heat the parts and apply wax, as it cools it draws the wax down the threads.

machine shops use a mig welder. You have to watch the heat, keep it on low.
http://4x4preservation.com/forums/showthread.php?t=382

 

[HybridMX6]

Re: oops! just purchased boat w/bad motor!

If the bolt snapped off but the head is still on the engine, the head should come off, possibly leaving some of the broken bolt exposed to try to get pliers on. The head is not threaded, so if it's hanging on it's just hanging on by deposits. Some heat should break it free, as well as possibly some light taps with a rubber mallet on the sides of the head(s). I had two break off on me on a 60hp 3cyl. Still got the head off, which left me some bolt to try to grab onto. I managed to get one out with vice grips and some heat, the other wasn't happening. Paid machine shop $5 to extract it, and they got it out without drilling.

 

[giannini7]

Re: oops! just purchased boat w/bad motor!

okay! got the head off! woho! the bolts are stuck in the head and the no.1 cylinder looks pretty scored. wheres best place to get omc manual?

 

[HybridMX6]

Re: oops! just purchased boat w/bad motor!

Honestly, on ebay. I've got two from there for under $40 each after shipping.