To bore or not to bore???

[fishinscott]

My motor is an '89 TE150SLCEM (S/N:R08241230), and I've got the powerhead completely torn down for rebuild (broke the crankshaft). I've heard from a couple of different sources that my motor can very easily be modified to a 175HP by simply boring the intake and exhaust ports larger. My OMC service manual indicates that the cylinder bore for the 175HP is 3.625", while the 150HP is listed at 3.500" nominal.

Being kind of a "leave well enough alone" guy, I'm always hesitant to try cranking up the performance at the potential cost of reliability. However, the 150 is a little sluggish getting out of the hole when I've got a passenger and full livewells.

<U>Questions:</U>
1. Can I have the cylinders and ports bored out and continue to enjoy what has been a very reliable motor ?
2. If I increase the output of the powerhead, do I need to beef up anything between the powerhead and the prop to handle the extra beefcake?

Thanks in advance for the expert advice I know I'm going to receive, and a special thanks to all of the veterans and active duty armed forces that are on our boards.

HAPPY MEMORIAL DAY

[EtecRanger 205]

Boring out to 175 specs, will not be your only requirement. You will need to change carb jets, and possiblely different carbs. Also timng and powerpacks might be involved. I would clean up the clylinders and use new pistons, rebuild as a 150, and look for reproping. Good luck

[fishinscott]

Okay, so I was going over the block with a fine-tooth comb, and found something troubling. The area of the crank case where the crank shaft seal ring rides has some excessive wear ! I think it probably occured when the crankshaft broke, but I guess that's irrelevant at this point.

I'll attempt to attach some pics, but I seem to have a challenge in that area. I measured the wear groove, and it's about .020" deep.



My question is, is there any option for having this area machined or am I scwewed?

Oh for the love of god, I just want to go fishing!!!!!

Oh yeah, and thanks for the help guys!

[Garfish]

I'd have to agree with Gary, Have the sleeves bored .30 over, install new crank and pistons and be done with, and for Heavens sake go fishing with a reliable motor................G

[luvdmymerc]

As long as you use the same sealing rings in the same grooves you should be fine.

[gearcaseman]

The block can't be bored that far because there's not enough sleeve material to allow it. There are no oversize sealing rings available for your situation. If you use the block in this condition, you will have an excessive end gap at the seal ring, possibly resulting in less than satisfactory performance. Another block might be the best alternative at this point.

[Lockjaw]

And you would have to have it ported.

There are a couple things you can do. Add a set of boyesen reeds, and find a set of intake filler blocks from an outboard recycler. Both of those mod's will add a little response and punch. Not ton's, but a little.

You can also open up the cowl. The two intakes have a plastic plate in them, and you can take that out. It lets more air into the cowl. Might increase engine noise a little.

[ChampioNman]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gearcaseman &raquo;</TD></TR><TR><TD CLASS="quote">The block can't be bored that far because there's not enough sleeve material to allow it. There are no oversize sealing rings available for your situation. If you use the block in this condition, you will have an excessive end gap at the seal ring, possibly resulting in less than satisfactory performance. Another block might be the best alternative at this point. </TD></TR></TABLE>

+1 ditto what Eddie says. Is that the bottom half or top half of the block?

[fishinscott]

It's the very first one at the top of the block. The crankshaft broke right off where the first connecting rod journal connects to the counterweight (at the flywheel end).

I don't know if this wear caused the break or if the break caused this wear, but when I got the motor apart, there were some aluminum shavings right up where the counterweight sits in the block, so it was probably caused by the break.

Wow, if my block is unusable, am I out of luck with this motor? Do I have any options for a used block that's going to be rebuildable?

Thanks guys!!

[ChampioNman]

I should have rephrased my reply is it on the front half (carb side) or the rear half (piston) side?

[fishinscott]

The first pics are on the carb side. Here's one of the same journal that's on the piston side.

Alright, since I'm getting so good at this picture thing, here's on of the broken crank shaft.

[ChampioNman]

Did you get a crank yet? You may be in luck I'm pretty sure I have a 2.6GT block in the shop and all your stuff will go into it. I'll have to check the bore though.

[fishinscott]

I did get a crank. It's used, but everything measures out perfectly. It's too bad that I can't use this block. The cylinders measure out perfectly, and it's in great condition (except for that one spot).

With the 2.6GT block, will all of the mounting holes (for the powerpack and stuff) be in the same spots or will I need to improvise?

Thanks!!

[ChampioNman]

everything is the same, bad news I just micro'd the block it is a GT175. 3.625.

[fishinscott]

I appreciate the information GCMan. If you have a line on a block, I'd much appreciate it. I am trying to figure out what my options are at this point.

Thanks!!

[Dhadley]

When you're looking for a block, any of the V6 crossflows with the flat exhaust paltes will bolt up. The 2.6 style crossflow with the "bubbled" exhaust plates won't bolt to your adaptor plate correctly. If Champ or one of the other guys doesn't have a line on one shoot me an IM and I'll get you a couple numbers to call.

[fishinscott]

CM,
I found something local, but I'm not sure if it will work. Can you tell me if the powerhead would work? If so, I can go and have a look at it. Here's the info on the complete powerhead that's available on Craigslist:

150 Johnson V6 parts motor (Tacoma)

--------------------------------------------------------------------------------
Reply to: sale-687627810@craigslist.org
Date: 2008-05-20, 9:13AM PDT

1986 extra long 25" shaft Model 155WTXCDR Serial J7159234.
power tilt is sold but still have most everything else. Call for more details.

Power head with crank $300.

Plus a lot more. Open to offers on everything.

Thanks!!

[ChampioNman]

Yep that will work only thing you'll have to do is swap electronics (stator, timer base and flywheel) no biggy. That is a 10 amp system yours is a 35 amp system. The mid won't work as it is 25".

[fishinscott]

Wow! Post number 13000...do you get some kind of award for that ? I feel honored that you would spend your 13000th post on little ol' me

Congratulations!!!

[gearcaseman]

Championman is a straight up Dude that enjoys helping others, he deserves that pat on the back you just gave him. Now, back to your situation. All these possibilities are good, the deal on the 150 H.P. is great. If you decided on the big bore block that Championman has, you would need to change the adapter plate as mentioned earlier. For cost and simplicity, you're better off with the 150 stuff.