A couple of ?'s

[bsh21wash]

I have a 91 seaswirl 4.3 omc cobra Do i need to prime the engine or anything? Sorry for the dumb question im a newbie. Also when a I shut the engine off it "diesled" how do I fix this?

 

[Haut Medoc]

Re: A couple of ?'s

You need to provide a source of water to cool the engine while out of the water......
When was the last time a tune up was done?......​

 

[Don S]

Re: A couple of ?'s

Dieseling can be caused by to high an idle rpm, wrong timing, or shutting the engine down without allowing it to idle for a minute or so before shutting off.

As far as priming goes. If you mean with gas, NO. Of course, it is a carb not fuel injection and needs to have the choke set when cold and possibly pump the throttle once or twice.

 

[mike11374]

Re: A couple of ?'s

I used to have deiseling with an OMC that I had and fixed by running a higher grade of gas. I'm no expert but that worked for me.

 

[Don S]

Re: A couple of ?'s

I used to have deiseling with an OMC that I had and fixed by running a higher grade of gas. I'm no expert but that worked for me.

The OMC 4.3L engines should all be able to run on regular gas. IF you have to use higher octane fuel just to get it to stop dieseling, then all you are doing is masking the problem using higher octane, not fixing the root of the problem. It's also the most expensive way to stop dieseling.

 

[bsh21wash]

Re: A couple of ?'s

What do you mean provide cooling when out of the water? I launch my boat and drive for awhile, take it out, pull the drain plug and park it. Am I forgetting anything?

 

[Don S]

Re: A couple of ?'s

What do you mean provide cooling when out of the water? I launch my boat and drive for awhile, take it out, pull the drain plug and park it. Am I forgetting anything?

Can I assume that things like flushing the engine and drive after use (especially if using in salt or brackish water) and preventive maintenance is not something on the top of your TO DO list.
Basically, If you have a problem, ask about it, Otherwise run it till it pukes....... is that about it?

 

[Bondo]

Re: A couple of ?'s

Also when a I shut the engine off it "diesled" how do I fix this?

A Full,+ Complete Tune-Up is a Start,......

Backing the Timing off a couple of degrees Helps,........

 

[bsh21wash]

Re: A couple of ?'s

Okay for one you took me the wrong the way, The boat has just been serviced by the dealer I bought it from. Also I'm running in fresh water. So your saying I need to flush the engine and drive everytime I get back? I do check oil levels and things like that.

 

[bsh21wash]

Re: A couple of ?'s

Haut Medoc
Vice Admiral
Join Date: Jun 2004
Location: seattle, wa
Posts: 5,693

Re: A couple of ?'s

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You need to provide a source of water to cool the engine while out of the water......
When was the last time a tune up was done?......




What did you mean by this??

 

[Haut Medoc]

Re: A couple of ?'s

If you run it while out of the water (say, while it is sitting on a trailer) you must provide water to the outdrive using a hose & 'muffs'.....
It would have been helpful if you had mentioned that it had been serviced by a dealer at the beginning of the thread.......
What was 'serviced'?......
On a tune up the dieseling should have been noticed & addressed.....
BTW, if you are running in freshwater there is no need to flush....
But that is critical in salt water use......
Like Bondo said, check the timing.....​

 

[Bondo]

Re: A couple of ?'s

Okay for one you took me the wrong the way, The boat has just been serviced by the dealer I bought it from. Also I'm running in fresh water. I do check oil levels and things like that.

It would have been helpful if you had mentioned that it had been serviced by a dealer at the beginning of the thread.......

Ayuh,....... Answering a Question that's Missing Most of the pertinent Info,......
Is alittle Tuff,.....

You Should check All the Fluid Levels in Any motor you're about to start,.....
'course,...... Most people Don't,+ That's what keeps Mechanics so Busy.....

I've Fired drivers who seemed to Think that Just because there was Oil in their motor Yesterday,... It Don't need Checking today......

And,..... As Haut says,.....
If you Just bought this boat, with a Fresh Tune-up,.....
Bring it Back,...... They got it Wrong,.... It's Dieseling......

 

[bsh21wash]

Re: A couple of ?'s

Okay thanks. How often should I change the lower unit oil?

 

[Haut Medoc]

Re: A couple of ?'s

Every year at the end of the season.....
This will also allow you to observe if you have any water intrusion issues....
Which you can address in the off season if necessary......​

 

[bsh21wash]

Re: A couple of ?'s

really? My buddy from work says he changes every couple times out.

 

[Gary H NC]

Re: A couple of ?'s

If your buddy is changing it that often he must have a leak. Once a season under normal use is all that is needed..

 

[bsh21wash]

Re: A couple of ?'s

Sorry for all the questions, but should I drain the water out of the manifolds everytime I get home? What kind of oil do I use in the block? I am assuming regular oil but have no clue, service manual is on its way. Anything else I should check before a day of boating?

 

[Haut Medoc]

Re: A couple of ?'s

No, not if there is no danger of freezing temps.....
I do know it gets a little colder down south....
If you use it in salt water you must (should) flush it on the muffs after every use......
Merc. 25w-40 or any straight 30 wt will do.......​

 

[bsh21wash]

Re: A couple of ?'s

Thanks... One more ? My boat kind of clunks when I shift, is this normal?

 

[Gary H NC]

Re: A couple of ?'s

A small clunk is normal. If adjusted correctly it should shift into gear without hardly any force on the control handle.Shift it quick and don't let it grind.It should idle around 600 rpms..