Few 5.8 Inc questions

[Hildebrand]

Hi, I have done searches but didn't come up with much. 5.8 cobra , and I want to change the oil, can I do this just like!e you do a car ? Also, I want to change the fuel filter , can I just twist of the old and twist a new one on? The guy before me had a new lower unit installed right before I bought it and I think the cables need adjusted because sometimes it's tricky to find d neutral and sometimes clunks going into drive but not everytime. How hard is the adjustment on these or should I have a shop do the adjustment ? Lastly, I have a three blade prop thats a 17 pitch and I wanted something that will help me get on plan better with more of a load in it. Just two guys and it's right on plane but with four it takes a second, maybe that's just normal because I'm new to boats . Thank you for your time!!!

 

[KM7]

Changing the oil:

There are 2 basic methods 1) From the top using a suction device or 2) from the drain plug.
If you have one, using a suction pump electric or manual is easy, simple and less messy, but I will explain both.


Either method:
Check your oil level before you start. Connect your hose adapter/muffs and turn on the water.
Start the engine and warm it up.

Shut off motor and water.

1) Suction method
Open oil cap and run the hose down the oil tube. Feel when it hits the bottom of the drain pan.
Take note of how much hose went down and be sure that you are actually at the bottom of the pan.

Place your oil container outside the boat on the ground lower that the engine if possible.
Start pumping. Oil will be hot!! When you start sucking air, you are done. You wont be able to get every last bit of the old oil with this method but it’s still pretty good.

2) From the drain plug
Find the drain plug on the bottom of the engine. See if there is a nipple and a shutoff valve attached to it. If so, attach a clear plastic hose to it an then run the hose out the drain hole in the back of the boat at the transom. Drop the hose down to your oil container.
Open the valve, remove the oil cap as well to allow air to enter at the top and prevent suction.
When is stops flowing you are done. If you want to get out a little more of the old oil out pour a fresh quart in at the top at the oil cap and let it drain.
Close the valve, Remove the hose.

If there is no fitting for a hose attached to the drain plug. Go buy an oil suction pump and use method 1)

Both methods:
Change the oil filter.
And yes they just twist off. Use a clean rag to get a grip on it before you hands get oily. It will be very full of HOT oil so be careful. Smear a light film of oil on the new filter before you screw it on and only Hand tight!

​​​​​​​Add the correct about of oil to the engine. Note it probably will not take the full capacity because you did not get it all out, so check with the dipstick as you get close to full.
Start motor. Let it run for a minute and shut it off. Wait 5 minutes for the oil to settle back down and check the oil level again.

 

[Hildebrand]

I think I'm going to buy a suction and do it that way
​​​​​​. Thanks

 

[HT32BSX115]

Hi, I have done searches but didn't come up with much. 5.8 cobra , and I want to change the oil, can I do this just like!e you do a car ? Also, I want to change the fuel filter , can I just twist of the old and twist a new one on? The guy before me had a new lower unit installed right before I bought it and I think the cables need adjusted because sometimes it's tricky to find d neutral and sometimes clunks going into drive but not everytime. How hard is the adjustment on these or should I have a shop do the adjustment ? Lastly, I have a three blade prop thats a 17 pitch and I wanted something that will help me get on plan better with more of a load in it. Just two guys and it's right on plane but with four it takes a second, maybe that's just normal because I'm new to boats . Thank you for your time!!!

Howdy,

We're going to need more info on what you have. There have been many changes in the Cobras from 1986 to 1998 when OMC went out of business.

1. Oil filters and fuel filters are pretty generic. You're on the right track there.

2. shift adjustment is pretty important, but we must know what you have, Dog-clutch, Interim cone-clutch or SX. Without knowing your model number it's impossible to proceed.

3. Propeller selection. In general, propeller diameter and pitch are (somewhat narrowly) determined by how you want to use the boat and the maximum recommended RPM (range) your engine operates.

I. E. just about all engine manufacturers suggest "propping" for a WOT [wide open throttle] RPM of MAX when operating the boat loaded with full fuel, and typical load (people, dogs, gear, etc) at the pressure altitude (i.E. Lake Tahoe 6200 MSL altitude.......or Sea level) you will normally run the boat. (this assumes the boat is loaded for proper CG [center of gravity] I.E. you don't have 4 300-pounders sitting on the transom!!......... and trimmed [drive-angle] for max speed)

There were some max RPM differences from different models over the years...... 200-400 RPM can make significant difference in top speed and holeshot if you prop to the wrong max RPM.

ALL the above parameters are of course dependent on whether the engine is optimally tuned and running correct (timing, plugs, EFI, worn out etc)

In general, you'll get a little better holeshot (good for towing wake boards and skiiing) if you use a 4-blade prop as opposed to a 3 blade but it will be a little slower for top speed.

Here's examples of 5.8 OMC model numbers

584AMLMED 1989
584APRMED 1989


584AMLPWS 1990
584APRPWS 1990

584APLRGD 1991
584APRRGD 1991

584APLAMH 1992
584APLAMK 1992
584APRAMH 1992
584APRAMK 1992
584DPEAMH 1992
584DPEAMK 1992

584APLJVB 1993
584APRJVB 1993
584DPEJVB 1993
584DPPJVB 1993
58FAPEJVB 1993
58FAPLJVB 1993
58FAPLJVN 1993
58FAPPJVB 1993
58FAPRJVB 1993
58FAPRJVN 1993
58FBPEJVB 1993

584ACPMDA 1994
584AGPMDA 1994
58FACPMDA 1994
58FACPMDM 1994
58FAGPMDA 1994
58FAGPMDM 1994
58FBDPMDA 1994

584APHUB 1995
584APHUE 1995
58FAPHUB 1995
58FAPHUE 1995
58FBPHUB 1995
58FBPHUE 1995

584APNCA 1996
584APNCS 1996
58FBPNCA 1996
58FCPNCA 1996
58FCPNCS 1996

Once you determine what you have, you can find part numbers at http://epc.brp.com/

Regards,

Rick

 

[Hildebrand]

Thanks for your replies. It’s a 1990. I’m new to boats so I want to make sure I cover all the basics

 

[Lou C]

I looked up your year and I think you're lucky because this engine package has:

1) the more common dog clutch Cobra, with fairly good parts availability
2) simple points and condenser ignition with no NLA mystery boxes
3) simple Holley carb that you can get rebuild kits and parts for easily

some of the later model ones with the cone clutch interim Cobra before the joint venture models, and the ones with electronic ignition and EFI are a real headache due to the lack of these specialized parts.

about changing the oil, you will find it fastest and easiest to use a vacuum oil changer with the garden hose female adapter attached to the larger diameter hose. This will screw on the threads at the top of the dipstick tube (be sure to put a garden hose gasket in the female fitting) and it will suck the oil out much faster than the thin tube will.

 

[HT32BSX115]

Thanks for your replies. It’s a 1990. I’m new to boats so I want to make sure I cover all the basics

Just an aside, I remember now your other post where you might have revealed the year model.

But for everyone else, it REALLY helps if you use year AND especially the model number because boat manufacturers VERY frequently DON'T use same year engine/drive packages in their boats!

So just providing the boat model year doesn't help much at all and we end up doing a lot of "back and forth" trying to figure out what you have.

It's pretty important for 90's OMC Cobras since for several years, there were 3 VERY different drives in use. Some good, some better and some VERY BAD. (Dog-clutch, SX, Interim)

So even if you post all the info in another thread, don't assume that everybody reading a newer thread will be "all-up" on what you have!

You could either ref: the other thread or just copy/paste the info into the newer thread. Saves all of us a lot of time trying to figure out what you have and how to fix your problem! :thumb:

All this stuff on how to get the best out of the forum is HERE:-------->https://forums.iboats.com/forum/eng...69-must-have-technical-information-for-diyers

Here's an excerpt.......

[h=2]MUST HAVE Technical Information for DIYers.[/h] August 7th, 2009, 05:28 PM



If you have NEVER posted in this forum before, please click on How to ask a question link first.

1. How to Ask a Question .... Please Read This Before Posting A Question...

Cheers,

Rick

 

[Lou C]

Yep that model # is the most important thing.

 

[Hildebrand]

The model number on the engine tag is 584APRMED and 986037. Yes, it’s also got the holly carb.

 

[Hildebrand]

Also, I’m done with the other post because the outdrive oil is changed and I took it out tonight and put a few miles on it and it was all good.

 

[HT32BSX115]

Also, I’m done with the other post because the outdrive oil is changed and I took it out tonight and put a few miles on it and it was all good.

:thumb:

The model number on the engine tag is 584APRMED

1990 boat 1989 engine/drive!

Good job! Check your drive oil a couple more times in the next month or so just to catch any bubbles that might migrate to the top that will lower the level.

After a couple of heat/cool cycles, you'll pretty much get all the air out of the oil and the level will stabilize.

I know I said it before but if you run it a LOT all summer, either change it at the end of summer or at the very least, drain a little out the bottom after it sits for several days before winterization just to see if you have any water intrusion.

You definitely want to know that before it sits all winter! And if you live where it freezes, be sure to drain the block and manifolds!

For adjustments, try to find yourself an OMC OEM manual that specifically includes 584APRMED for procedures on adjusting a lower shift cable and other stuff!

Also, have a look at http://www.hastings.org/~stuart/cobra/ There's a fair amount of historical info there.



Hope you have a great boating Summer !!

 

[Hildebrand]

I will be sure to check the oil after the next few times out. I live in Michigan so it does get cold , but I will change it at the end of the season just to make sure it’s good. Also, I’m going to read the link you posted and get a manual so I can read about the cables. The guy before be had a new lower unit put on before I bought it but didn’t say why he did. When I had the boat winterized last fall the marina said it was the better lower unit that was put in. I just read a lot on here about the cables and how they need to be right and I feel like mine aren’t perfect like they should be and want to get them before I tear something up