1977 Omc 165

[diogee2]

I am currently looking at a 1977 Bellboy that has an OMC 165, I was able to take it out on the water a few days ago briefly. It ended up cracking the plastic fitting on the forward part of the exhaust manifold used for cooling and we were towed back in. I have a few questions about some things that happened before the fitting broke. 1. It seems like it took a little while for the RPM's to build up after putting the throttle forward, is this normal. I am used to outboards and they respond immediately with throttle movement. 2. When initially put under load to accelerate there was a little pinging, it stopped when up to speed. I know this can be caused by numerous things, the boat had been in storage for 3 years and hadn't been out on the water, could this be bad gas and/or what else should I look for. 3. There was a little smoke coming out of the recirculation hose from valve cover to carb, after it was shutdown, is this normal for this year of boat. It doesn't smoke at all while running or start. Anything else you guys can think of I should check would be great. Thanks ahead of time.

 

[rs2k]

Re: 1977 Omc 165

Getting parts for that motor can be difficult. The GM 250 hasn't been used for a very long time. I would recommend looking for something that has a small block Chevy. If you are looking to get a boat this old you will either need to be mechanically inclined or you will need to spend a lot of money at the shop.

Pinging under acceleration could be caused by bad gas or incorrect ignition timing.

Depending on how the boat is propped and the size of the boat it can take several seconds to go to full RPM from a dead stop. Once on plane the throttle should respond quickly, but not like a two stroke will.

What color was the smoke that came out of the hose? Did it have a smell?

 

[rs2k]

Re: 1977 Omc 165

Does the tilt system work smoothly? Check the oil in the low end, top end, and bell housing of the stringer. Ask the owner what type of oil he put in the low end. The model is most likely electric shift and it uses a special oil. You CANNOT put normal gear oil in an electric shift OMC. Check to see what the oil looks like in the engine. Check a spark plugs if you can. Even better, check them all and run a compression test.

How long was your test run? Did it show any signs of overheating?

A lot of people will tell you to avoid the OMC stringers, but as long as they are maintained correctly they are bullet proof and in many ways better than a Mercruiser. They sure are expensive to fix though!

 

[diogee2]

Re: 1977 Omc 165

The oil looked fine,will check the plugs when I go back. The tilt motor worked just fine. The smoke out of the recirculation hose was very light almost like a little bit of blow by. The boat has been owned by the same family since new and was stored indoors 10 months out of the years. The boat is perfect and I know a repower is in my future, I am just trying to find out how long in the future. I believe myself to be mechanically inclinied, I have rebuilt many motors from VW to AMC 360's. We were only out for about 15-20 minutes, and it was slowly warming up, then the coolant fitting on the front of the exhaust manifold cracked and then it just got hot quick and we shut it down. I just know certain motors have certain things to look for. I am kinda thinkin a compression check when I go back and check out the plugs. Hope this gives a little more insight. Oh and I don't think its an electric shift, Its a normal throttle with the center button you pull out for neutral and push in to shift. So again anything else I should look at would be great, what kinda of compression numbers am I looking for also. thanks.

 

[Zeeter]

Re: 1977 Omc 165

I would be a whole lot more concerned about the drive than I would be the engine. You can rebuild that motor blindfolded. Drive parts are getting really rare and expensive if you can find them,

 

[rs2k]

Re: 1977 Omc 165

All OMC stringers built before 1980 were electric shift. If the prop has a cone on it than it is an electric shift. If it has through hub exhaust than it is mechanical shift. My electric shift OMC has been trouble free and has the same throttle system you described.

 

[diogee2]

Re: 1977 Omc 165

Theres no cone on the hub, its a through hub exhaust, so I am looking at a mechanical shift. That being said, it seemed to shift tilt, and drive fine. I will be taking it back on the water next weekend after his mechanics replaces the coolant fitting. as far as the outdrive anythin special to check there. I have always had outboards, so this I/O is new to me.

 

[rs2k]

Re: 1977 Omc 165

Make sure you check the oil for water contamination. That's about the only way those drives go out from what I've read. As long as they are maintained correctly they are excellent out drives. I wish they still made them. Make sure you look at the ball gears. You can use them until 1/3 of the balls' width remain. The ball gears are in between the bell housing and the upper end of the out drive. You can see them when the out drive is raised. Make sure you don't run for very long with the drive in the up position and never more than idle. It accelerates the ball gear wear like crazy.

They tilt high, turn very tight, have very strong impellers, no hydraulics to go bad, no bellows to sink your boat, no gimble bearings to go bad, and are very easy to winterize. Boats that received stringer drives are also better built to handle the increased load on the stringers.

Both my twin engine cabin cruiser and my 18 foot tri-hull have stringers. Both boats can spin on the spot when the drives are hard over. Amazing turn radius.

The major downside with the stringer is that the parts are either hard to find or are expensive, but so far I haven't had any trouble finding what I needed for my three stringers.

 

[diogee2]

Re: 1977 Omc 165

I will check the oil and gears also, thanks. What kind of numbers should I see for the compression check and what kinda range should they all be within in realation to each other. Thanks

 

[rs2k]

Re: 1977 Omc 165

The compression ratio for that engine is 8.02:1 and the compression should be 130 PSI. According to the service manual, the spread should be within 25%. In other words the lowest reading should not be less than 75% of the highest reading. If the best cylinder reads 140 PSI than the worst cylinder should not be below 105 PSI. I like to see results closer to 10% - 15% though. If the best cylinder reads 140 PSI than the worst should not read less than about 120 PSI.

You can download a service manual here:
http://www.4shared.com/file/102988421/c4f26d54/OMC_64-86.html


If you are positive that the boat is a '77 than that means that the low end was changed out within the last 29 years. The hydro-mechanical shift drives first appeared in 1980 and the full mechanical drives appeared in 1982. You can tell a mechanical and hydro-mechanical shift apart by looking for an anode hole in the out drive.

Look here:
http://www.sterndrive.info/800_lower_repair_cost.html

 

[diogee2]

Re: 1977 Omc 165

Awesome, Thanks for the link.

 

[diogee2]

Re: 1977 Omc 165

OK my mistake, there is a cone on the prop and it doesn't have the little notch. I am trying to upload a few pics now

 

[diogee2]

Re: 1977 Omc 165

http://s945.photobucket.com/albums/ad293/diogee2/?albumview=slideshow

these are the few pictures I have so far.

 

[rs2k]

Re: 1977 Omc 165

That is a good looking boat... At least from the back. I'd like to see the rest of it. The shape of a boat can give you a good idea on the shape of a motor and out drive. That's definitely an electric shift. I have one just like it with a Chevy 305 V8 except mine has a different steering setup. Can you post some photos of the engine when you get a chance?

 

[diogee2]

Re: 1977 Omc 165

I updated the photo link with pictures of the engine and boat. It is a beautiful boat, the hull itself its almost purfect. I went this weekend with the intention taking it home, but after the fitting broke and it died after 15 min I couldn't make myself do it. My wife would have probably made me sleep in the garage with the boat. So with any luck it will be fixed and next saturday I will do the 3 hour drive test run and tow it home. So now I know its an Electric shift any special areas to pay attention to?

 

[diogee2]

Re: 1977 Omc 165

The service manual link appears to be broken, does anyone else have one I can use to study up before this weekend. Thanks

 

[diogee2]

Re: 1977 Omc 165

Anyone?? Good Link for manual?

 

[WizeOne]

Re: 1977 Omc 165

Buy a Seloc manual or keep your eye out on ebay for a factory manual.

Another thing to keep firmly in mind is DO NOT run with the outdrive in any up position, exept maybe 15-20% for short periods at low speed to get out of shallow water. The tilt system on your boat is not intended as a trim system and will cause rapid wear of the drive ball gears and eventual bearing and case failure if you use it that way.

A curiousity that I know you won't be able to address is the hose flush attachment on the port side pivot trunion. I've never seen that before and was unaware that that side had access into the water passageway???

 

[rs2k]

Re: 1977 Omc 165

A curiousity that I know you won't be able to address is the hose flush attachment on the port side pivot trunion. I've never seen that before and was unaware that that side had access into the water passageway???

My electric shift also has that adapter. I've also seen them on ebay before. The water passages goes from the upper out drive to the pivot trunnions. Both of my mechanical shift stringers have radiator flush adapters on the hose that leads from the intermediate housing inside the boat, but I could put that adapter on them if I wanted to. You cannot use muffs on any stringer drive. Make sure you NEVER forget to put the cap back on when boating. If you don't put the cap on then the engines won't get water.

Here is another link to the manual:
http://4-ghillie.com/props/OMC-64-86.pdf

 

[diogee2]

Re: 1977 Omc 165

Thanks for the link, it works great. The hose fitting on the left side of the outdrive seemed to work great for flushing and testing the motor and it looked original.