need help with omc

[exhaustedguy]

hello to all on this forum! I was hoping some of you boat wizes could help me out? My uncle bought an 89 OMC with a 2.3 liter last year. We are both automotive mechanics but need a little more understanding on what might be going on with his boat. It runs like a top! smooth as can be but when you bring her up to speed at full throttle, around 4k rpm it shuts down but does not die. it will still give fuel but only sit and idle until you back the throttle back down. Then you can go again. You can drive around all day at 3500 but at 4k it will go about 15 seconds. I see no electronic or vac gov controls on the carb. I feel like it may be ignition control related? It has a mallary distributor. no vac advance. Every experience I have ever had with mallary has been not so good so I was hoping somebody might know a direction to point us?

 

[danond]

Re: need help with omc

Welcome to iBoats!

I would recommend you get a manual from eBay for that engine and drive. There are many marine-specific things to know about it. Being a car guy can be helpful, but it can be a hindrance (and dangerous).

That engine has points; have you checked them out?

 

[Gary H NC]

Re: need help with omc

Welcome to Iboats!

Sounds like a fuel delivery issue.
Could be a clogged pick up screen in the tank.Or a stuck anti siphon check valve.
Another possible cause is the fuel vent like is clogged up....bugs love to nest in them.

Try running with the gas cap loose and see if it changes anything.A plugged fuel vent line will create a vacuum in the tank and starve the fuel pump..

Also make sure all fuel filters are changed..

This is the very detailed Real factory manual...worth every dime.
The after market books like Seloc and Clymer are only good for cleaning up oil spills...don't waste the money..

http://cgi.ebay.com/ebaymotors/1989...ANUAL-NEW_W0QQitemZ200343101304QQcmdZViewItem

 

[exhaustedguy]

Re: need help with omc

We will try the fuel cap thing next time out. we ran it with the dog house off and I watched down the carb and it was till dumping fuel when it would drop off. I just find it kinda funny that it will sit and idle while the throttle is wide open. We did not check in the distributor yet. I thought all mallory ignitions were laser pickup and not points? runs so good from idle to 3900 I couldnt see bad points. does it have some kind of electronic advance or spark control? I will tell him to go get that book as well...good thing to have anyways.