Thread:

OMC 2.6 GT questions

Against my better judgement, I bought another boat....more of a project. It's a 18'10" Lavey Sebring tunnel with a V6 OMC on it...only tags on the cowl say 2.6 GT. The price was right...$500. Looks like it was setup at the factory for center steer, and has a foot throttle....it's beat but the bottom looks fast.

I got it home and after having difficulties getting it to fire, decided a compression test was in order....I'm seeing about 80-90 psi on all holes. Seems low. I pulled the carbs to clean them up and noticed a bunch of port work before the reeds....seems someone at one point did some work to the thing, and it was supposedly rebuilt about 5 years ago. The engine is supposedly an '85. Are there any other identifying features on it to figure out what the engine really is?

Should I bother with this thing with these kind of compression numbers or should I punt. Finally talked to the last guy to run the boat, and he said that it'll start and run no problem if you keep the quick start thing engaged for 30 seconds or so...which seemed to work. Once it's warmed up, seems to start and run great on the trailer (with water of course). The guy also told me that when getting on plane or coming off of plane you have to push the key in to keep it from bogging out...LOL...looks like we need some jet work too.

cool, thats reassuring. i'll call Al next week and chat with him about it.

they didn't make a 19 ft sebring ,its either a 18' 10'' or a 20.2 .if you have pics i would love too see . i can help you out alot with setup on the 20.2 since i owned one for quite a while !!!TUNNEL T



PS HERES A FEW OF MY OLD RIDE!

Compression tests should be around 125 to 130#. That's what mine average. You may need to put a bit of oil in the cylinders or run it. What are the part numbers on the heads? They should be one number off on the last digit and start with 325....

Give me a model number and I'll look it up. If it is what you say, it is a great motor. Premium fuel ONLY. And a max of 24 degrees of timing set at 4500 rpm!

Pushing the key in to make it not bog indicates a lean issue. Clean the carbs and fuel system. I have done away with the vacuum pump(s) and have an external electric with a bypass regulator, set at 3 3/4psi.

Life is good!!!

numbers on the heads are:

325638 and 325639

dunno where to look for more numbers

Originally Posted by TUNNEL T

they didn't make a 19 ft sebring ,its either a 18' 10'' or a 20.2 .if you have pics i would love too see . i can help you out alot with setup on the 20.2 since i owned one for quite a while !!!TUNNEL T



PS HERES A FEW OF MY OLD RIDE!

heres a pic of my dash..... factory center steer???


mine measures about 18'8" tip to tail

Originally Posted by Forkin' Crazy

Give me a model number and I'll look it up. If it is what you say, it is a great motor. Premium fuel ONLY. And a max of 24 degrees of timing set at 4500 rpm!

FC, you sure about that? The V8's of that vintage are basically oversized versions of the V6 (2 more cylinders, same bore/stroke/pistons, carbs, etc), and they only ran 16* total timing.

Check the book or run it by Al before making any timing changes.

Originally Posted by STV_Keith

FC, you sure about that? The V8's of that vintage are basically oversized versions of the V6 (2 more cylinders, same bore/stroke/pistons, carbs, etc), and they only ran 16* total timing.

Check the book or run it by Al before making any timing changes.

1. FC is correct..
2. The V8 is a overgrown version of a V6 Looper... The motor being talked about here is a bubble back Crossflow

Originally Posted by lbhsbz

numbers on the heads are:

325638 and 325639

dunno where to look for more numbers

That is the ones.

Originally Posted by STV_Keith

FC, you sure about that? The V8's of that vintage are basically oversized versions of the V6 (2 more cylinders, same bore/stroke/pistons, carbs, etc), and they only ran 16* total timing.

Check the book or run it by Al before making any timing changes.

Positively. The 2.6 is a crossflow. The 2.7 was the first looper in 1986. Plus none of the loopers I am aware of except the F1 V8s had two piece heads.

Originally Posted by lbhsbz

Well...the boat is going to the dump. After spending the better part of the week fixing the crack in the deck...correctly, I uncovered the fact that the transom is ready to fall off...and the only thing holding the motor on is the braces that catch the stringers....I found another "deal"....stay tuned...this oughta get good...like most deals I find.

DON'T DUMP THE MOTOR!!! Mine will run over 95 on my Allison!!!!