1975 Omc Out Drive 400/800

Hey Guys and Gals
I have a 1975 OMC outdrive 400 electric shift. I took it to a mechanic because all of a sudden it stopped shifting. I did not know it had electric shift. Needless to say all that was wrong was I had knocked some wires loose. By the time the mechanic was done he wiped out my lower unit. It looked like he took a hammer to my shifter coils. He had a lower unit he would sell me though. I got my boat back from him after spending $700 for him to try to rip me off. Now I need a lower unit. My question is, will a OMC 800 lower unit fit a 400 upper unit. I was told the only difference between the two was the gearing in the upper. Is this correct? Thanks for any help.

Jeff

Re: 1975 Omc Out Drive 400/800

Your dates do not match. 400/800 did not show up until 1978. If it is an Electric Shift, there are two basic Uppers. Some parts are interchangeable, but not a bolt on replacement. Changing out the Gear Sets requires some special tools and knowledge because a complete Reseal will probably be needed. With the price of Upper Gear Sets you would be much better off and search the Internet (Ebay, Iboats and others) for an exact replacement. If you have some pictures of the Outdrive, I and others on this forum can help you ID the drive. Also, if you plan to do the work yourself, after the Drive is Identified, You should get an OMC Parts Catalogue and Service Manual for your specific model. Welcome to Iboats!

Re: 1975 Omc Out Drive 400/800

Sorry about that all the upper stuff. A lower unit for an 400/800 is different than a 1975. If your Lower has slits on the side of the casing for muffs then it could be a 400/800. If they do not have those slits you have an older unit and the Lower will be different.

Re: 1975 Omc Out Drive 400/800

Curious, if you took it to a mechanic and he destroyed it when all that was wrong was a wire loose, why is he not replacing it for you?

I might not understand the industry, but I would think that a mechanic would start with the "obvious" or simple diagnostics first, and THEN tear the unit apart...

When mine stopped shifting, the first thing I did was check the shifter wiring. Once I found that the wiring was fine, THEN I did a tear-down. When I did the tear-down, I didn't destroy anything and I'm not a mechanic...

Just curious...

Re: 1975 Omc Out Drive 400/800

Thank you all for replying. The mechanic told me it was a 400. It does not have slits in the side so it must be a pre 400. As long as I get a lower unit from the same time frame should it fit on my upper??? The out drive bolts to a 140 horse power straight four. This he told me was a chevy motor. Is there a difference in the OMC out drives of that period for the motor sizes. All I need is the lower. My upper is in good shape. The mechanic took it apart and resealed it he said just to make sure!!!! He wanted to sell me a lower unit he had in stock. That is why he tore my lower apart. It also had a oil fill screw that the threads were messed up on.

Thanks
jwburnett

Re: 1975 Omc Out Drive 400/800

The lower units from Early 70's thru 77 are darn near interchangable. How much does the Mechanic want for the Lower and how much to install it. More over do you trust him? Not sure if I would with what you stated he did. Ebay has lowers all the time and I believe Iboats also. There will be other on the Forum that should chime in soon here on some of the nuances.

Re: 1975 Omc Out Drive 400/800

if he ruined the outdrive how do you know all that was wrong was loose wires? If you fixed the loose wires and it worked, why did you go on from there?

Re: 1975 Omc Out Drive 400/800

are you sure it's your drive he tore up or another one he is saying is yours? Seems odd to me

Re: 1975 Omc Out Drive 400/800

Good morning Guys

The mechanic and the owner of the shop are two different people. I had the boat out two weeks prior, and the lower unit worked great. After that I replaced the motor cover and pinched the wires too the lower unit. At this time I did not know about the electric shift in these units. When I put the boat back into the water the lower unit would not shift at all. That is when I took it to the shop. A week later I stopped in and talked to the mechanic. He told me he found the broke wires and repaired them. He said the motor was shifting and all they had to do is take it to the water and test it. He said to check back in a couple of days. When I called back the next weekend, that is when the owner told me he had disasembled everything and I was going to have to replace the lower unit. I ask him how much I would have in it. He told me $2500. I told him to box things up and I would be up to pick up my boat. He told me to bring him $750 for the work completed. I asked him what work was done. He said he had to replace the seals in the upper. The upper was not leaking??? The rest of the money was for inspecting the unit. When I went through the parts I found the wire twisted off on the the shifting coil. It is the bigger coil. I believe this is for reverse?? Also the coil pack looked as if it was hit or pryed on, it is shot. The only other thing wrong with the lower unit is the oil fill screw hole is stripped out. It is the top oil screw. It might be able to be repaired. If I could fix the threads, all I need for the motor is the shifter coil. Thanks for all your replies.

JWBURNETT