1988 OMC 4.3 stutter and bog down

[astuckey]

Hi I have a 1988 Four Winns 205 Sundowner with a 4.3 195 V6. The problem started this year when water skiing with a 15x17 pitch prop. When accelerating, the engine will bog down and the RPM's will go from normal to a slower speed and back again a few times quickly before getting on a plane. Note that there is NO backfire or popping noise. This problem will happen regardless of prop pitch (15x17 or 14 1/2x19), and number of people onboard. It will not do this every time you accelerate, but it usually happens. I am not sure if this is a coincidence, but it seems to be worse when the engine is warm and has been running for a while. Today I was on my way home, a accelerated from idle and went almost full throttle, when it got really bad. It sputtered and stuttered a LOT and would not get above 3000 RPM without pulling the throttle back and pushing it forwards slowly. It seams to be less of a problem when accelerating slowly. We thought the accelerator pump in the carb might be bad, but it seamed alright after taking the top of the carb off and inspecting it, and it sprayed fuel when the throttle was moved with the engine off so...? Also, the RPM needle hesitates slightly to go down when it has reached about 1700 RPM when stopping the boat. I am not sure if these problems are related.

Could is be the exhaust flappers? Also, it almost seams like it is being starved for fuel in the seveir cases of the problem.

Things we have done:
Replaced the fuel filter/water separator
Taken the top of the carb off and drained all fuel in the bowl
Checked wire connections on starter solenoid
Checked spark on Cyl# 1 and 2 with in line spark tester
Used carb/choke cleaner with engine running
At the beginning of the season:
Changed oil and oil filter
Replaced fuel filter/water separator
Checked timing and point gap (they were perfect)
Cleaned distributer cap, points and roter
Changed both belts
Changed the lower unit water pump

I have no idea where to go from here, please help.

 

[Bondo]

Re: 1988 OMC 4.3 stutter and bog down

Replaced the fuel filter/water separator
Taken the top of the carb off and drained all fuel in the bowl

Ayuh,... Was there any Crud in the old filter,..??

Ya shoulda rebuilt the carb, rather than just glancin' at it...
Was there any visible Crud in the fuel bowl,..??

 

[astuckey]

Re: 1988 OMC 4.3 stutter and bog down

There was some stuff in the fuel bowl and i haven't checked the oil filter yet but I will soon. Do you think it is the carb?
Thanks

 

[Bondo]

Re: 1988 OMC 4.3 stutter and bog down

Do you think it is the carb?

Ayuh,... My guess is, some of that crud got past the bowl...

 

[mpdive]

Re: 1988 OMC 4.3 stutter and bog down

Float could be wet or be set wrong. I would replace filters and rework the carb. Certainly would give the problems you described.

 

[astuckey]

Re: 1988 OMC 4.3 stutter and bog down

Just got back from testing, we disconnected the ESA from the coil after moving the lever that controls the ESA and nothing happened. (yes it was idling and we also tried it at 900 rpm) We left the wire off (which shut the tach off) and took it for a spin and the problem was *pretty much fixed. I am wondering if it could be the ESA and not the switch with the lever that controles the ESA. We have already ordered a new ESA because we are switching to electronic ignition over the winter. I will also rebuild the carb over the winter like you sugested, because there is still an *extreamly slight problem when accelorating fast, and there was some crud in the fuel.
Thanks for the help.

 

[astuckey]

Re: 1988 OMC 4.3 stutter and bog down

When the ESA is disconnected everything is fine. Could this be the coil?

 

[proshadetree]

Re: 1988 OMC 4.3 stutter and bog down

If it is fine it should not be the coil.

 

[astuckey]

Re: 1988 OMC 4.3 stutter and bog down

We tested the coil and it was pretty much ok. There is still a little problem without the ESA connected, and its not the tach or tach wires. Tomorrow we are going to replace the points condenser and coil, I think the condenser is the main problem.
Thanks for the help!

 

[astuckey]

Re: 1988 OMC 4.3 stutter and bog down

When we put 12 volts to the coil everything was fine even with the ESA connected. We tried to cut down the resistor wire which helped but did not fix it. We also replaced the starter solenoid because there was no voltage increase at the the coil when starting. We are now getting a new ESA from cdi because CDI thought that they sent us a bad esa.