83 3.8 OMC stops at 3000rpm????

jawzzy

Petty Officer 2nd Class
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Sep 16, 2002
Messages
154
took the boat out today for it's first run, and everything was fine till I decided to let her go. It's starts to take off no probem, bow in the air, and then when it hit's 3000rpm, just about to start it's plane out, the engine just bogs, like we hit something, and quits. At first we thought we did hit something, but after trying again same thing, but this time it wouldn't start. I just put in 2 new batteries, and yet it tryed to turn over like they were both dead. After get a boost, it still took almost 5 minutes before it finally kicked in and started. We checked spark, and had it, so it seems to be a fuel related problem I guess. I did put in a new water seperator this spring. The only thing I did different this year for winterizing was to put flogging oil in the carb. <br />I'm going to check out the spark plugs tomorrow, but I would think a bad plug would just cause chugging, not kill the engine all together. We then ran it for over 2 hours at 2000rpm without a glitch. I then tried full out again, and it died everytime at 3000rpm, and I restarted everytime with no problem. <br />Does any one have an experience with this problem, or any suggestions, thanks!!!!!!!!!!!!!!
 

Boatist

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Apr 22, 2002
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4,552
Re: 83 3.8 OMC stops at 3000rpm????

I would check the fuel pressure at the carb. You need at least 3.5 lb of pressure at the carb. I would also your fuel seperator and make sure you do not have any air leaks. Did you install the fuel seperator before or after the fuel pump.<br />If you have correct pressure then I would check the distributor advance and make sure it is working correctly.
 

jawzzy

Petty Officer 2nd Class
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Sep 16, 2002
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154
Re: 83 3.8 OMC stops at 3000rpm????

I just replaced the old set up, before the fuel pump. Any suggestions on how to test the filter for air leaks? I will also check out the distributor advance, thanks!
 

Boatist

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Apr 22, 2002
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Re: 83 3.8 OMC stops at 3000rpm????

I would start by doing a fuel presure test at the carb. As far as air leaks just make sure everything has a good gasket and is tight. One more thing you might try is remove the fuel filler cab. I have seen the vent get plugged up and and tank has a big suction.<br />I must admit I have never seen a 3.8L OMC engine. If it has a 4 barrel carb could be float is stuck for the back so when the back two open all you get is more air but no more fuel.
 

hoot

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Sep 8, 2002
Messages
434
Re: 83 3.8 OMC stops at 3000rpm????

check timing and ignition coil. my boat would run fine up to 3200 rpm and bog down. replaced coil and problem was gone.
 

jawzzy

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Sep 16, 2002
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154
Re: 83 3.8 OMC stops at 3000rpm????

Thanks guys, I'll look into all those things too, but talking to an OMC guy here in Canada, he's sure my new water filter is already full since I didn't fill the tank last fall, and probably took on alot of water this winter and spring. Once it stops raining around here, I'll get out and check it out.
 

pine island fred

Lieutenant Junior Grade
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Dec 20, 2002
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1,144
Re: 83 3.8 OMC stops at 3000rpm????

if you can get to it, pull the fuel pick up tube in the gas tank. probably has a finger filter screen in it. big hunks of debris in the tank will clog up this filter good luck fred.
 

jawzzy

Petty Officer 2nd Class
Joined
Sep 16, 2002
Messages
154
Re: 83 3.8 OMC stops at 3000rpm????

Well, I emptied the fuel/water filter, and no water at all. So that isn't it! I changed the coil, points, cap, rotor, plugs and wires, and the fuel filter in the carb itself. All that's left to do is rebuild the carb:) I managed to run it past the 3000rpm limit in the driveway, but I know it's not the same as being under the pressure of pushing it through the water. Will try and test run tomorrow, and update!
 

WSUDERMAN

Petty Officer 2nd Class
Joined
Sep 9, 2001
Messages
176
Re: 83 3.8 OMC stops at 3000rpm????

One more thing to check (you may have already but i did not see it listed.) Timing Advance. Since its an 83' i would guess it's a mech advance in the distributor. maybe its stuck? Not sure what the specs are but @ 3000 rpm your timing should be somewhere near 32 deg BTDC.
 

metwrench

Petty Officer 3rd Class
Joined
Aug 16, 2003
Messages
86
Re: 83 3.8 OMC stops at 3000rpm????

I would Guess with the others, Advance on Distributor...check with a Timing light, Or Physically Check the weights and Make sure they are moving out and the springs are rusted to heck.<br /><br />Dropping a Little OIL on the center of the shaft under the rotor is what we used to do to keep them Oiled and Functioning.<br /><br />4 barrel carb ? Metering valves..what type of carb ? on Rochesters, they are a common problem..also are EASY to get at and adjustable
 

cobra 3.0

Lieutenant Commander
Joined
Jul 31, 2003
Messages
1,797
Re: 83 3.8 OMC stops at 3000rpm????

Is your starter staying engaged?
 

jawzzy

Petty Officer 2nd Class
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Sep 16, 2002
Messages
154
Re: 83 3.8 OMC stops at 3000rpm????

Well, THANKS for all the help guys, but I think I got it. With replacing all the above items, it passed the test run with flying colours, and is running great. I think my milage might even of improved (I sure hope so;). <br />Thanks again for all the suggestions, and your help on this one!!!!!!!!!!!!
 
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