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floater1

Regular Contributor
"Glad I found this forum. Rea

"Glad I found this forum. Read a few threads and did some searching and everyone seems very knowledgable here. Must be many current or ex OMC techs here. I have a few issues in getting my '78 OMC running properly (I'll post those later) but for now I'm trying to find out what carb came stock on this motor? It currently has a Holley 450 carb. Its a Chev motor for sure and the valve covers say 225 on them so I assume that means 225 horsepower? I assume its a 350 rather than a 305 (no where on the motor can I find for sure which one it is). I'm just trying to find out if this is the original carb, and if not, which one was?
Btw, this engine is in a '78 Glastron/Carlson CVX-18 if that helps.

Thanks in advance,

Rob"
 
original carb was a Rochester

original carb was a Rochester quadrajet - omc part number 0981705

Engine is a 305 Chev.
 
That was fast! Thank you. Th

That was fast! Thank you. The Holley needs a rebuild kit so I hope to do that soon. Interesting that the little 305 would make 225 horses unless thats the torque rating?
 
"If you can find the engine mo

"If you can find the engine model number (should be on a plate on one of the valve covers), it should identify for sure what the engine is. Follow this link to see how to read your model number.

http://www.marineengine.com/manuals/omc_sterndrive/order_1980-93.html

I've been trying to find the HP on mine forever, but no one could ever tell me for sure (even got a couple of "who cares, as long as it runs good"!). But from what I can find in general, the 305 (5.0L) seems to be between 200 and 225 HP. With the 4 bbl carb, it seems to be either 215 or 225 HP. With the 2 bbl carb, it seems to be 200 HP. This is just speculation though, and I'm not sure what else goes into determining the HP."
 
"I went to the parts book for

"I went to the parts book for the 1978 225HP and looked up the pistons - OMC simply used the Chevrolet part numbers for internal engine parts- number shown is for chevy 305 pistons - same pistons as my 229 V6 (3.8)as well.

Quadrajets kick ass on boats....small primaries for cruising give decent mpg

This summer I had my g/f drive and I watched to see when the secondaries opened....they started to really open up at 3600 rpm on my boat, so I cruise about 100 rpm below that usually"
 
"Can anyone tell what the firi

"Can anyone tell what the firing order for this 225 would be? My OMC service manual shows the firing order for the 185,200,230, and 260 models. It also shows a firing order for the 250 model which is different that the others. Nowhere does it even acknowledge the 225 model.

For some reason I can only pull about 2200 rpms out of this engine at full throttle. My timing is advanced pretty far but I still should be able to get way more rpm out of her. Have a set of points, rotor and cap, so I just want to make sure my spark plug wires are intact and hooked up properly. Nothing like troubleshooting."
 
"Thank you. In my book it see

"Thank you. In my book it seems to state the order for all OMC engines except mine but I would think all sbc's are all the same anyway.

Can't even get up on plane and I had the throttle all the way forward. I played with it back and forth but still would not go more than about 2200 rpms. I checked the throttle linkage at the carb and it seems correct.

Put on new cap, rotor, points, condensor. Checked plug wires all intact and connected properly. I wanted to retime it today only to discover my 30 year old fuel pump gave it up today.

I should note that this motor was seized after it sat for a few years. We got it unseized last spring and it ran good and I was able to pull normal rpm with it then. The oil and filter after oil change then wasn't as bad as I though it would be after the unseizing. Its just been recently that I can't pull the normal rpm with it. Could some rust or gunk have worked its way into a position so I've got a dead or half functional cylinder now? I plan to do a compression test once I get the proper tester. I'm thinking I may have a dead cylinder? Can't do anything now until I get a new fuel pump."
 
"Got the new fuel pump on toda

"Got the new fuel pump on today. Checked distributor thinking the pin at the bottom of it may have been damaged but it looked fine. Checked all plugs and they are running rich. After removing everything I was able to get to the timing gear and crank gear. I discovered the timing mark on the timing gear was at the 12 noon position (per the GM bible it should be at the 6 o'clock position). I'm somewhat amazed that the timing mark turned 180 degrees. I suspected it turned when I unseized the engine but just not that much. After 30 years its time to replace the original timing chain and gear set anyhow. Also got at the trim motor so I'll hook it up to 12 volts and see if its the motor, possibly just a fuse and/or the brushes/armature are just stuck from lack of use. I spent the whole day working on this and I have learned so much. I was fortunate to have a relative walk me through this. Beats paying a high buck shop who doesn't really care or know how to work on your older equipment."
 
"I can kiss my motor goodbye.

"I can kiss my motor goodbye. Compression test is horrible. Tried soaking the cylinders. Did water injection into the engine in hopes of freeing up the rings to no avail. Very frustrating. I now see the terms low hours or minimal use in a whole new light, especially in regards to marine engines. Its kind of like use it or lose it, literally. Say goodbye to a low hour original OMC. If I'm lucky I will have a stout 350 in it by spring.

Sorry for the rant but I tried posting a pic of my engine for you all to see but this is what it reads.

"Error
One or more of the images or attachments you uploaded exceeded the maximum allowable upload size (which is 100 kilobytes). These images or attachments have been removed from your post. If you would like to include images or attachments, upload new files after you make sure that the size is not greater than 100 kilobytes."

Uh, this is a picture I had on picturetrail its not like its poster size or anything."
 
Robert...that's too bad ab

Robert...that's too bad about your engine. If picturetrail is one of those public picture hosting sites then just post the url (link) to it and people can go and see. Unfortunately 100kb is not very big when trying to post pics.
 
"Now that my boat is up and ou

"Now that my boat is up and out of the water,my OMC out drives don't look too good. They seem to have a lot of corrosion. The sacrificial anodes don't seem to be badly eroded. I am wondering if this is an electrical problem? If so where do I start checking? Are the anodes perhaps the wrong material? Every year I go through the ritual of cleaning the corrosion and repaint the out-drives and clean the anodes. Is there some special paint out there that will hold for more than one season, without the paint baking process."
 
"chiefalan, My compression tes

"chiefalan, My compression test results are as follows:

#1=120
#2=120
#3=150
#4=didn't test fuel filter in the way
#5=96
#6=88
#7=120
#8=120

I have about a dozen or so bolts left to go and I will be pulling the engine out and tearing it all apart. I may have been quick to write this engine off in my earlier post. I'd prefer to keep this engine if possible but I won't know for sure until I rip apart the internals."
 
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