Offshore Mid Question

[Short Gambler]

Can someone explain the advantage to an offshore mid on a bass motor? Or the difference between standard, hp or offshore. Just remember it's on a 90's 2.5 bass boat. Thankx

[Markus]

The offshore mid is a lot stronger.

In addition, it is a lot louder, and the exhaust exit might improve holeshot.

[Fish]

...it also looks and sounds cooler. :D :D

[Short Gambler]

I agree it sounds better... bout what does one cost? advanages?

[Fish]

arguably you get a little better hole shot than a through or over hub, the exhaust exits a bit more freely and it is a stronger mid section. Most of the newer mids that came on the 260 and 280 do not have the traditional offshore exhaust look. Instead they have holes drilled in the bottom of the can (I believe 5x 1/2" holes on each side) above the cav plate. It would appear the exhaust relief is important since merc still does it on their hi-po motors though. Many members have done the same (drilled) and there are some great articles on it including a step by step modification with pictures doen by talon 2.5 if you do a search. Lots of folks say this mod is really loud though, but then again, the offshore is not quiet either.

One thing most suggest not doing is drilling the vertical surface of the mid or doing the bob's offshore modification. I am sure I will get more than a few comments from others about theirs working fine, but the argument against it is that drilling or cutting the vertical surface weakens the structural integrity in a part of the mid that gets a lot of stress. Several people here have done it and cracked their mids. Many others have not, but with drilling up from the bottom on the horizontal surface like mercury does achieving the same exhaust result without weakening it, why do it on the horizontal surface and take the chance? Additionally, it will be quieter when idling by water police.

Having said that, I still bought an offshore mid and am very happy I did. You can usually find them for 1000-1300 complete depending on how clean they are. Occasionally one will pop up cheaper but you have to be patient and quick when it does.

BTW, if you do not already have one, you will need a trim pump to mount inside your boat with trim lines to the mid (not like some of the mids that have the pump and ram all in the mid). Bob's used to sell them but lots of guys use the mercruiser trim pump for this application.

[Short Gambler]

Thanks Fish, that does help... so any mid 90's 2.5 should fit my motor, then I need to buy a pump, right? The noise is not a problem, me likey loud!!!

[Fish]

yep, that should do it. powerhead bolt patterns will be the same, but a few bolts might be slightly different lengths depending on the adapter you are corrently running. Dont forget the trim lines too (from the pump to the mid). Check the buy and sell section, they pop up from time to time.

[Short Gambler]

Thankx again

[stvhelm]

Here is one advantage to an offshore mid



http://forums.screamandfly.com/forums/attachment.php?attachmentid=96019

[Short Gambler]

Nice!!! What caused that? 100+ with wood in the way?

[stvhelm]

Didnt hit nothing. just a matter of time. Speed, vibration, harmonics, all take there toll.

[halveb]

I had one fail this summer where the lower unit bolts on either side of the drive shaft. Replaced with another hi-perf straight leg (only ran $100) but next time will go with an offshore.

[Short Gambler]

Is there a weight difference in a stndard and offshore?

[stvhelm]

yes, the offshore is around 20lb heavier

[Short Gambler]

Thankx, Dell

[QUICKSILVER]

BTW, if you do not already have one, you will need a trim pump to mount inside your boat with trim lines to the mid (not like some of the mids that have the pump and ram all in the mid). Bob's used to sell them but lots of guys use the mercruiser trim pump for this application.[/QUOTE]



Not exactly true. You can bolt the offshore mid to the center style trim unit. You can also still use your two peice base plate. I have done both. In other words, you only need the offshore center section. Your trim and base plate can be re-used. It would save you lots of money.

[Short Gambler]

Now, thats what I wanted to here!!! I have a 1991 2.5 EFI Mariner, what year mid will work with my trim setup now...Thanks Quicksilver