'84 Lund 3.0L IO engine runs, locks up, runs, locks up

[Scott Danforth]

Is there a good manual online or that a guy can purchase to go through the trans?

Pm me your email

 

[alldodge]

VP manuals are on line but need to know the serial number. That said the special tools needed to rebuild will be costly. I spent over 700 just to rebuild the lower on my Bravo

https://www.volvopenta.com/en-us/service-and-support/your-engine/manuals-and-handbooks/

 

[Lou C]

I found this confusing to follow. First you said it’s a 3.0 Volvo. Then next it’s an OMC Cobra. So which is it? If the Cobra and no oil over the upper gears you will need a rebuilt upper gear housing at the least. Those units take approx 2 qts of gear oil and have to be filled correctly. If you want to test the engine pull the drive and hook up water to the impeller and run the engine. If it doesn’t lock up then your problem is the outdrive. Reman gear housings are generally available for the Cobra drives you have to make sure the drive ratio is correct.

 

[Scott Danforth]

I found this confusing to follow. First you said it’s a 3.0 Volvo. Then next it’s an OMC Cobra. So which is it? If the Cobra and no oil over the upper gears you will need a rebuilt upper gear housing at the least. Those units take approx 2 qts of gear oil and have to be filled correctly. If you want to test the engine pull the drive and hook up water to the impeller and run the engine. If it doesn’t lock up then your problem is the outdrive. Reman gear housings are generally available for the Cobra drives you have to make sure the drive ratio is correct.

if its a 1984 lund with a 3.0 volvo, it would have an AQ270 drive on it
the OMC Cobra came out in late 1985, so if the boat is a 1984 it would not have a cobra
could be a franken boat

 

[bigtoyz]

I was going by what the dealer was telling me based on the the serial # stamped tag. I even ordered a head gasket based on it. Last night I got more serious about identifying it. No sticker but GM is on the block. Thats when I found the Cobra and serial numbers on the OMC outdrive. I was thinking engine problems all this time and now with help from you guys I think Im rebuilding the Cobra outdrive this winter. I still trying to understand the Penta/mercruiser/GM differences. The engine is Blue beneath the grey paint. Both engine and have been replaced is what previous owner told me.

 

[Scott Danforth]

blue is old OMC colors (pre 1980)
suggest you post pictures of your drive and engine because you have a frankenboat

 

[Lou C]

Yep that light blue is old OMC colors, the Cobras were all a charcoal grey, engines and drive/transom mount
Does your drive look like this?

 

[bigtoyz]

I will post pics of what I have as soon as I get home. The med blue paint is covered w a medium grey, making it look like a reman engine. The parts guy stood right next to it as I got the ID tag #s off the transom. the drive does look like the 2 pics. Originally the plug/emblem came out on the previous owner and he drove it back to shore, said water was pumping out the side instead of into the engine.

 

[bigtoyz]

(ENG)Pic 1&2 show the gray paint over the blue. I can not find a tag but right above the Starter is cast in the block a large GM and next to it is 2769040. Stamped in is MO 927EJB
(DRIVE) OMC cobra Serial TO513462.
I pulled the cover and everything is dry in the gear area. I expected broken teeth or shavings but it was actually very clean, no broken teeth, etc. Im still going to rebuild it but thats what I found.
The black plug is where the emblem popped out. He sealed a plug back in.

 

[Lou C]

well you got a Cobra for sure. When you took the top cover off were the gears covered in oil, or not?
It looks like the engine is from an older OMC boat because of the color, but it may not really matter.

 

[Scott Danforth]

to put an OMG Cobra in a 1984 boat meant that the boat originally had a mercruiser in it

 

[Lou C]

agreed there must have been some strange story there, or the OMC stuff was free lol....

 

[bigtoyz]

So a cobra originally was bolted to a mercruiser eng in this boat? So is this most likely a GM, VolvoPenta, or or mercruiser engine? I was just looking and it looks like the lower end is a lighter grey that the upper.
No, there wasnt even a trace of oil in the upper case.

 

[Scott Danforth]

So a cobra originally was bolted to a mercruiser eng in this boat? So is this most likely a GM, VolvoPenta, or or mercruiser engine? I was just looking and it looks like the lower end is a lighter grey that the upper.
No, there wasnt even a trace of oil in the upper case.

No, a mercruiser engine and drive was originally bolted into your boat. that is the only other drive hole that the cobra could fit. By the looks of it, the prior owner found an earlier motor and bolted it to a later drive and installed in the boat.

OMC drives for 1984 and 1985 were stringer drives. they had a transom hole big enough to crawl thru. literally a 16" x 16" square hole with rounded corners

the volvo penta AQ series drives had a hole slightly smaller

so for a 1984 lund, the only motor/drive that would have come with the boat unless your transom was patched would have been a Mercruiser

 

[bigtoyz]

So this engine would be an older Merc or Chevy engine or did Merc install Chev production motors? I read that this is pretty much a Chevy II engine. And will a later 4 cyl mercruiser 3.0 will bolt to this drive? Ive heard volvo penta parts are extremely hard to find anymore. And I now have to find out if VP headgaskets are the same as this motor as that is what I just installed.

 

[Scott Danforth]

GM sold the longblocks to Mercruiser, OMC, Volvo, etc. However all the bits bolted on to turn a forklift motor to a boat motor are designed and manufactured by the marinizing OEM

The 3.0 (181 cubic inch) is an industrial only version of the 153 cubic inch ( 2.5 liter) motor that debuted in 1962 (4 cylinder veraion of the 230 cubic inch 6 cylinder)

The head gaskets are GM, made by Mahle. So it doesnt matter who you buy base engine parts from. However from a GM industrial engine dealer is the least expensive.

Being formerly blue, your motor was marinized by OMC between 1974 and 1979.

Checking the casting numbers would help

 

[bigtoyz]

Wow, you given me sooooo much more useful info than the dealer has.
So it is an industrial GM 181 (3.0) engine made for marine use? And I ask for merc parts rather than VP, chevy, or OMC? The cast number tells me the actual yr of the motor? And the model number for the drive is on the tag on the drive? M: 985042 S: T0513462 The manual info you sent said VP but I am guessing it applys to the Cobra?

 

[Scott Danforth]

No, you stated volvo with the thread title, the manual I sent is volvo. However you have an OMC. Completely different

Dont confuse serial numbers with GM casting numbers

 

[bigtoyz]

So the serial numbers are the ones stamped into a machined part on the block? Where would I be able to find a manual for the cobra?

 

[Scott Danforth]

So the serial numbers are the ones stamped into a machined part on the block? Where would I be able to find a manual for the cobra?

engine serial number from GM is, however the OMC serial number will be on a stamped tag just above the starter boss.

the GM engine casting numbers are the ones cast into the side of the block

here is a link that will help https://www.perfprotech.com/blog/bo...ines-block-id-codes-4-cylinder-marine-engines