4.3 v6 cuttin out above half throttle???

M

Martyn191

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Sep 3, 2011
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Hi all, im new to this site but seems like a good place to start with some issues i have with my boat!

I have a 1988 renkien elite 1700 with an omc 4.3v6, and a volvo penta sx stern drive! took it out for its first run the other day every thing is fine until above half throttle. the engine just seems to cut out or start to miss fire I think the engine number is GM6269732 214

Return the throttle to neautral and it starts fine straight away and will run all day at low speed

Any help on this would be great!!

Thanks in advance Martyn!
 
Lou C

Lou C

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Joined
Nov 10, 2002
Messages
11,832
Re: 4.3 v6 cuttin out above half throttle???

Things to check include general tune up specs (dwell, timing, total timing advance, plugs, wires) and the fuel system for any restrictions. Fuel filter, vent, and anti siphon valve. The anti siphon valve on mine had corroded and the engine would not plane out the boat, it would hit 1500 rpm and that was it. Replaced the valve, rebuilt the carb, tune up and it was back to normal.
 
M

Martyn191

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Sep 3, 2011
Messages
3
Re: 4.3 v6 cuttin out above half throttle???

Lou C said:
Things to check include general tune up specs (dwell, timing, total timing advance, plugs, wires) and the fuel system for any restrictions. Fuel filter, vent, and anti siphon valve. The anti siphon valve on mine had corroded and the engine would not plane out the boat, it would hit 1500 rpm and that was it. Replaced the valve, rebuilt the carb, tune up and it was back to normal.
Click to expand...

Thankyou for your quick reply, i am away for 2 weeks for work but will check these things as soon as i am back and let you know how things go!

Regards Martyn!
 
M

Martyn191

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Sep 3, 2011
Messages
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Re: 4.3 v6 cuttin out above half throttle???

Hi have finally had some time to look at the boat today, replaced fuel seperator, the filter in the carb, cleaned anti syphon valve, also installed a gauge after the fuel pump and the fuel pressure is a solid 7 psi at ideal and the same up the rev range! points and rotor arm are new (previous owner changed these) how do i check the dwell? going to run the engine on new fuel tommorow from a seperate tank aswell as the fuel in the tank may be quite old!

Engine still seems to hesitate a little every now and then at idle and also smells like the mix is quite rich as the exhaust fumes smell likefuel!

Regards Martyn!
 
Lou C

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,832
Re: 4.3 v6 cuttin out above half throttle???

You need an engine analyzer that you can hook up to the coil, to check dwell. Dwell and point gap are inversely related, as the gap gets bigger the dwell gets smaller and vice versa. You can use the same analyzer to check the idle speed, and it sounds like your carb is too rich, you may have to adjust the idle mixture. First set dwell, then idle, then timing.
 
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