OMC help needed....????

jawzzy

Petty Officer 2nd Class
Joined
Sep 16, 2002
Messages
154
Just urchased boat with an 83 OMC 3.8litre sterndrive and finally got it out today for the first time. Went pretty good, but have a number of questions:<br /><br />First, the engine would run a about 110F at low speed/rpms, but at 30mph/3000rpm and higher, it ran about 160F, which I know is still low enough, but am I looking at replacing the impeller, or is this normal?<br /><br />Second, the trim switch on the throttle doesn't seem to work at all. What should I be looking for here? And the up/down gage stays near the up position all the time, with very little movement. I would preseme the gage is inaccurate, although on take offs, the boat does not plain at all, keeping the bow up for what seems to be too long before it does plain out? <br /><br />Third, the main up/down for the outdrive worked fine, until I parked it in the driveway, then lowered it. It stopped half way down, and now won't do anything. Again, any suggestions here?<br /><br />Any ideas or advice would be greatly appreciated:) Thanks!!!!
 

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,072
Re: OMC help needed....????

Sounds like it is time to go hunting for electrical gremlins. You have to get a wiring diagram/manual and at least a test light (an ohm-meter would be better) and start tracing wires.<br /><br />Your sending unit that tells thge trim it is at it's limit could be jammed. There are tons of answers but the surefire way is to trace the wires first.<br /><br />Worst case scenario is your trim motor has died!<br /><br />As for your impellar it is good practice to do it at least every other season (once a season if you see allot of dirty water and sand). The 160 sounds a bit high but that is probably the temp thermostat you have.<br /><br />Bob
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: OMC help needed....????

My first question is which motor do you have. Is it the old stringer motor with the big rubber boot and quarter round gear to raise and lower outdrive. Is it a Cobra that uses two hydralic rams to raise outdrive.<br />I am going to assume the stringer motor, so every thing from her on if for the stringer. I have not herd of a 3.8L. The 4 cylinder is 3.0L 181 CI and 140 HP. The thermostate is a 150 degree so engine should not run as low as 110 degrees unless the thermostat is stuck open. 160 to 170 is normal for high RPMs.<br />The trim switch on the throttle actually runs a trim motor at the front of the engine to raise and lower the front of the motor and since outdrive controlled by the motor it changes the outdrive trim. The trim guage tell you is front of motor is up or down.<br />The outdrive tilt is run by a motor on port side that turns a worm gear to turn the gear that raised the outdrive. The motor will not run if the 50 amp fuse near the starter blows. Many reasons it may not rise, could be lack of grease, two solinoids, the tilt motor or the tilt clutch on the outdrive. Again this is all for the stringer system
 

jawzzy

Petty Officer 2nd Class
Joined
Sep 16, 2002
Messages
154
Re: OMC help needed....????

Thanks! <br /><br />It is a stringer, and yes it has both the hydralic trim for the motor itself, and the trim for the outdrive. I got the outdrive trim to work again today, but it was intermitent. From other reading here, I would presume I need to clean up the outdrive trim motor, and probably replace the brushes.<br /><br />As for the hydralic lift for the motor, all I get is a solinoid click, and that's it. I tried putting direct battery power to that trim motor, but all I got was sparks. The trim is stuck up high right now, so it appears the trim gage is right.<br /><br />As for the thermostat, I will have to check that out, probably during my winterizing. <br /><br />And yes, it's a 4barrel V6 3.8 litre buick engine.<br /><br />I am going to try and get to it this weekend with an ohm meter, but it seems everythings ok up until the solinoids anyway, considering the clicking I'm getting when using either trim switch.
 

jawzzy

Petty Officer 2nd Class
Joined
Sep 16, 2002
Messages
154
Re: OMC help needed....????

Well, it appears I may need a new trim motor. My manual is on the way, so I'll wait for it before disassembling it. All I get out of it is sparks, and all the wires and fuses seem to connect.
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: OMC help needed....????

Jawzzy<br />I think from your decription you have a Cobra Motor not the stringer.<br />I know very little about the Cobra but many other on here will be able to help you.
 

jawzzy

Petty Officer 2nd Class
Joined
Sep 16, 2002
Messages
154
Re: OMC help needed....????

Thanks, but I thought it was a stringer since that what I was told in another thread here. I was lead to believe that anything before 86 was a stringer, and after a cobra. Is that not right?. And if not, what is a sure way to tell which it is?<br /><br />And just to clarify, the trim motor that's not working lifts the WHOLE back end of the motor up and down with a hydralic system.
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: OMC help needed....????

Jawzzy<br />Your motor is a Cobra not a stringer.<br />Cobra has Hydrolic rams to lift outdrive. The outdrive bolts to the transom. I think most Cobra aes silver. Looks a lot like the merc.<br /><br />The stringer has a big 1/4 circle gear to raise outdrive. The outdrive does not bolt to the transom but to the motor bell houseing. The outdrive has a big rubber seal that bolts to the outdrive and on the outside of the seal bolts to the transom. They are usually White.<br />I am not sure what year they made the switch but some time after 1981.
 

Boatin Bob

Lieutenant Commander
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Sep 24, 2001
Messages
1,858
Re: OMC help needed....????

Boatist...I have to disagree. I think jawzzy has a stringer because of his year (83) and because he mentions 2 trim systems, one for the engine itself and the other for the drive. The one for the drive is really a tilt and shouldn't be used while running or you kiss your ball gears goodbye. The cobra has only one system which is the 2 hydraulic rams.<br /><br />Jawzzy...the Cobras were a charcoal color and most of the stringers were silver or white and some even said 400 or 800 on the top
 

jawzzy

Petty Officer 2nd Class
Joined
Sep 16, 2002
Messages
154
Re: OMC help needed....????

Well then, I'd have to day IT IS A STRINGER!!! It's white, has the big rubber boot, and 2 trim systems. Thanks for the tidbit on not using the outdrive trim for driving. Had to the only time out, and didn't know better. Hopefully one time doesn't hurt me, although that may explain why I'm now having trouble with that trim too? Got my comprehensive manual today, so things are starting to make more sense. My model is #384SPMRCNC. The manual states its for almost the same #, but ends in CTR instead of CNC. What difference would that make? <br /><br />I'm pricing out a new hydraulic pump now. I'm also checking to see if there's such a part as just a rebuil kit. The manual gives instructions on repairing it, so I would thinks a repair kit exists. <br /><br />Thanks for the help guys, and please keep it coming. I've learned alot so far, but alot more to go YET!!!!!!!!!!
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: OMC help needed....????

Boatin Bob<br />You may be right as he says has big rubber boot in last post. He also says has hydrolic lift for the motor. All the 400/800 I have seen had two gear driven motor for trim and tilt. One on the front of the motor for trim that drives a worm gear to the front motor mount. The tilt is from another motor on port side of engine with another worm gear to drive a clutch to the small gear. Is the hydrolic he is talking about the power steering. I know of no other hydrolics on a stringer.
 

Boatin Bob

Lieutenant Commander
Joined
Sep 24, 2001
Messages
1,858
Re: OMC help needed....????

jawzzy...those 3 characters actually tell the year of the motor, in your case CNC is a 1982 and CTR is 1983, it's quite common to see the previous year motor in a boat because the boat itself may have been built in 82 (later), the 38 at the beginning tells you it's a 3.8 ltr, go to this link to see what the entire model number means (don't worry about the text on the page). I had a 1984 800 that had a hydraulic pump and 2 cylinders mounted at the front of the engine, one on the port side and one on the stbd side, I didn't have the electric worm gear motor front centre that some had. model number web page
 

P.V.

Chief Petty Officer
Joined
Mar 14, 2002
Messages
452
Re: OMC help needed....????

Yep, it's a "83 Stringer. OMC made it the 3.8 from "82 to I think "84 or "85. The 3.8 was the first years of the "cut-off" V-8's. A 305 chevy with the 2 middle cylinders removed= 3.8 litres. A 350 ci with the 2 middles removed is a ....4.3 litre.
 

ndemge

Commander
Joined
Jul 15, 2002
Messages
2,644
Re: OMC help needed....????

Cool, I'm not the only once with the '82 OMC :) <br />Big ole rubber boot... by I have the gear, not hydrolic tilt.<br /><br />....how hard is it to change that boot? .. have a lil dry rot going
 

jawzzy

Petty Officer 2nd Class
Joined
Sep 16, 2002
Messages
154
Re: OMC help needed....????

Well now that I have the outdrive removed, it seems pretty simple, but will attack it in the spring. Just remove the 22 (or 16) screws, and the inner clamp, remove old boot, and install new one. A little crammed for working, but doable.
 

OH BOTHER

Recruit
Joined
Aug 18, 2003
Messages
5
Re: OMC help needed....????

I assume you know what Knuckle gears are now. When the out drive is up (tilt) you can see them. they used to be "round". Don't be alarmed if they are worn, they can go to 1/2 - 1/3 before they break. Designed to be run down, You can chew them up in moments (or beers). The others have a universal like the tractor (that goes bad to).<br />Carefull to check that new boot on the trim your fixing, your motor tilts and cut my boot. the back mounts settle.<br />You have 3 oil spots in that drive CHECK / CHange THEM ALL! (others have 1). Fill from bottom, ask someone.<br />Trim gage??? aren't you special! But remember trim goes up - motor goes down.
 

OH BOTHER

Recruit
Joined
Aug 18, 2003
Messages
5
Re: OMC help needed....????

"Third, the main up/down for the outdrive worked fine, until I parked it in the driveway, then lowered it. It stopped half way down, and now won't do anything. Again, any suggestions here?"<br />Mine does that too - I assume not enough power AND you can't put up while running (alt. power). Some times I get 2-3 ups, without the engine running then it stops. Lift it with some chick on the switch it works. Mines a renkin (sp? tree in he way), what's yours.
 

OH BOTHER

Recruit
Joined
Aug 18, 2003
Messages
5
Re: OMC help needed....????

"And yes, it's a 4barrel V6 3.8 litre buick engine." It's the 3.8 that they put in every midsized GM in the 80's. 1986 they redisigned it, made it ft. wheel and fuel injected (best 6 cil on mket today). The boat makes 5 for me, 2 currently. "4barrel" Can you get me the #'s when you find them????? I'd like to have the 4barrel also what's the trim gage look like maybe I can find one.
 

tmclendon

Seaman
Joined
Mar 31, 2003
Messages
74
Re: OMC help needed....????

Wow what a long thread. I have some things to add. I had a '83 3.8L 4-Barrel Stringer for 20 years, I loved that boat! Had VERY little trouble with it until about 2 years ago (I just sold it this year). Anyway:<br /><br />It's a CHEVY engine, not a Buick. It's usually called a 229 when used in cars. You'll find it in a number of mid-small sized chevys, camaros, berettas, etc. Remember this when you are looking for parts!<br /><br />It's rated at 185 HP with the 4-barrel (Rochester Q-jet), and 170 HP with a 2-barrel.<br /><br />First thing: BUY A SHOP MANUAL! Get the OMC if you can, any year 82-84 will work, and they cover all OMC outdrives (2.5-3.0-3.8-5.0-5.7, 400 and 800 outdrives), they show up on e-bay pretty often. If not get one of the Seloc, they are supposed to be pretty good.<br /><br />The first thing to check for the tilt problem is the 2 50-amp fuses on the bracket on top of the engine. They BOTH have to be intact for the tilt to work. One feeds the switch that activates the solenoids, one feeds the power side of the solenoid. Does it click when you hit the tilt button? If not, it's pretty sure that it's electrical, which is good news, as that's a hell of a lot easier to fix then the motor/clutch/gears. Now, drain the clutch housing (the semi-square box on the port side of the outdrive, has a bronze gear sticking out of it that engages the 1/4-moon gear that's bolted to the outdrive). There's a drain screw on the bottom and a fill screw on the side. Betcha it's full of water. Anyway drain it and fill with 30w motor oil, same as you put in the engine. It's **** near impossible to keep the clucth housing from filling up with water, all you can do is drain it and refill with oil regularly.<br /><br />The water pump impeller: A lot of folks say to change it every year or 2, but my first one lasted for 11 years, and the second one 9 and still going. Of course this was on an inland fresh/clean water lake, so if you are in dirty water, every year is probably good advise. By the way, don't try to change it yourself, it's a bear. <br /><br />Replacing the boot: Here's a write up I did on that a couple of weeks ago:<br /><br />I've done it twice. It IS a pain, but as the previous poster said it's nothing like taking the outdrive off!<br /><br />Hints: Do it on the trailer, not hanging from a hoist in your boathouse with you standing waist-deep in 40-degree water!<br /><br />A replacement boot is around 70 bucks.<br /><br />You CANNOT replace the metal plate that goes on the outside of the boot, it won't fit over the outdrive. Use the old one. Just wiggle the new boot through the old plate, nothing to it.<br /><br />You'll have to stretch the new boot some to get it over the outdrive, but it's not too hard. The boot is pretty tough! Spray some WD-40 on the inside if you want.<br /><br />Make sure you use a good marine sealant, but not a permament one! You may need to change the boot again sometime. Make sure whatever you use doesn't cure too fast!! It'll take 30+ minutes to get the new boot secured. I used 3M 4200 last time, seems to work fine.<br /><br />Adjust the tilt so the outdrive is more-or-less centered in the tansom hole.<br /><br />Don't use too much sealant, either on the transom or the flange on the outdrive. Too much will make a heck of a mess. Maybe a 1/4" bead on the transon, 1/8 on the flange on the outdrive.<br /><br />Obviously you attach the boot to the outdrive first with that giant hose clamp. You kinda pull the boot inside-out and get it on the flange (put the sealant on the flange first), Rotate it back and forth a little to smooth out the sealant, then line it up as best you can (with the screw holes in the transom), and tighten the clamp. <br /><br />Best hint I can give you: When you are screwing the boot to the transom, before you put on the sealant, stretch the new boot over the metal frame and line up the screw holes. The lip on the new boot will hold the plate in place. If you don't it's heck to get all the holes to line up, especially with sealant all over the place. Put the screws in loosley at first until you have them all started, then tighten them evenly. Do not overtighten! it's easy to deform the boot. Take 3-4 passes on all the screws, a little tighter each time.<br /><br />Use a power drill or a power screwdriver, there are bunch of them screws and your hand will be REALLY tired if you do them all manually.<br /><br />Go slowly, it's really not too hard as boat maintenance goes!<br /><br />Enjoy! You'll see lots of bad press here about the OMC Stringer, but like I said, I loved mine!<br /><br />Use the search function on this fourm, there is tons of info on the Stringer that you will want to read.<br /><br />Tom
 
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