Omc cobra Problems since upgrading ignition

Cruisinbye

Recruit
Joined
Jul 29, 2020
Messages
3
Hey guys, I need some help here. Six years ago we decided to do a tune up on our boat, 1990 four winns 180 horizon with a 4.3 omc cobra. At the time we figured changing points to hei ignition would be a good upgrade to do. Six years later we have had nothing but problems ever since. The tach is inaccurate, hard starts, loss of power while cruising, loss of top end speed by 10 mph, sometimes the boat just dies and needs to be towed into the dock. We have totally replaced the following chasing this issue; Fuel pump, anti syphon valve, new rebuilt carb from JET, alternator, ignition module, coil, plugs, wires, cap, rotor, shift cable went bad so that was replaced as well. Carb was replaced last week, couldnt get engine to fire so i checked everything and only had 4 volts going to the coil. Ran a jumper wire from coil to battery and she fired right up. So i ran a completely new wire from ignition switch to coil pos terminal and went to the lake. It started just fine except it shifts hard in and out of gears and will stall unless i push throttle far when shifting. Ran good around the lake for about 45 mins and I wanted to change the radio so i pulled back on the throttle and it died. Would not restart..... had to be towed in. When i was running it I did go full throttle a couple times and tach read close to 6k rpms, which i know the engine wasnt running that high and the tach was always accurate on this boat until the ignition upgrade. Decided to check my esa syatem and doing tons of research and my esa had been changed about 6-7 years ago to a cdi 123-9898p. Called cdi and the tech support said the module could be fried, as I have a msd blaster II coil on there by my mistake, so i am putting other coil back on and ordered new esa module from cdi 123-9800, which is supposed to be a beefed up module according to them. I also ordered new overstroke and interrupter switches from cdi as well. Does anybody believe this will solve my issues? Do i have more than 1 root issue going on here? Boat has 717 hours and was always stored in garage its whole entire life and always covered. All these issues started after swapping out ignition, we regret doing the tune up as before the tune up the boat would do 49 mph, now i can barely get 40, and it didnt get to 40 until i put new carb on it. This boat was my dads and been in my family since new, so i know the condition of it and what has been done to it. PLEASE HELP!!!!!!!!
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,802
When you removed the points did you keep the old Prestolite points distributor? If so just put it back in with a new set of points, condenser cap n rotor. I never advise people to get rid of points on these engines just for this reason. The basic Prestolite points system is fine, so you have to put in a new set of points and condenser every 4/5 seasons, that's it. The problems people have is everything in the system is set up for points, ie the coil used, the resistance wire and the ESA module as well. Ask the tech guys at CDI, if there is anything else you can do to work through the problems. But if you have the old distributor and coil PUT THEM BACK IN....
And yes my 4.3 still has points!
 
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Cruisinbye

Recruit
Joined
Jul 29, 2020
Messages
3
Found my issue guys....... The resistor wire from alternator to coil was causing my problem. Disconnected that wire and ran a new wire direct to coil from alternator and bam, problem fixed.
 
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