1988 3.0 OMC 2 issues

[chrisc1024]

I have a 1988 OMC 3.0L engine on our boat. I have 2 issues with it, with the second issue happening while attempting something the onsite mechanic recommended.

The engine runs and starts GREAT and we have it idling around 900RPM. The problem is under load we are only getting up to 9 knots and then the motor won't push any higher even though the trottle is wide open. We used to get about 24 knots at WOT. It ran great until after a long 2 hour trip up the Hudson to see the fireworks and a 45 minute trip back in. My brother ran the tank pretty low on that trip. The next time out is when he had this issue.
When they broke everything down, they found that the filter had sand in it and there was a small amout of sand in the filter at the carb as well.

We have installed a new carb (as the old on had a small hole in the bowl) which did not help. We then just replaced the fuel pump (which did have a good amout of build up when disassembled), which still did not help.

I'm now leaning towards an electrical problem. The only thing on the electircal side that has been done is all 3 starter coils have been replaced and the distributor was switched from points to electric which fixed our pinging issue and the boat ran great. All of this was change before the current problem.

When attempting to bypass and hooking up a wire directly from the battery to the coil (the on stie mechanic recommended this to rule everything before the coil as a culprit) my father accidently tapped the jumper wire to the - on the coil and we heard a POP. After that we lost spark. We swapped to a spare coil and still have no spark. I checked and we have 12V to the coil but don't have continuity from the - on the coil to ground. I haven't had time to pull out the wiring diagram but noticed that wires from the - go to the ESA module. Do you think that might have been the POP? Also, I couldn't find a fuse on the + or - going to the coil, so is there some type of reset switch I'm missing?

Any help would be GREATLY appreciated.. I need to fix the lose of spark issue before I can even get back to the main issue..... This is my first inboard as my old boat had an outboard....

Thanks!

 

[danond]

Re: 1988 3.0 OMC 2 issues

You need to get a factory service manual. You can find a link to an online copy via the Adults Only sticky in this forum, and/or you can purchase them from eBay.

Not a SELOC, not a Clymers. The factory, year-specific manual for your engine. It'll have priceless wiring diagrams and troubleshooting charts.

 

[xltier]

Re: 1988 3.0 OMC 2 issues

I have a 1988 OMC 3.0L engine on our boat. I have 2 issues with it, with the second issue happening while attempting something the onsite mechanic recommended.

The engine runs and starts GREAT and we have it idling around 900RPM. The problem is under load we are only getting up to 9 knots and then the motor won't push any higher even though the trottle is wide open. We used to get about 24 knots at WOT. It ran great until after a long 2 hour trip up the Hudson to see the fireworks and a 45 minute trip back in. My brother ran the tank pretty low on that trip. The next time out is when he had this issue.
When they broke everything down, they found that the filter had sand in it and there was a small amout of sand in the filter at the carb as well.

We have installed a new carb (as the old on had a small hole in the bowl) which did not help. We then just replaced the fuel pump (which did have a good amout of build up when disassembled), which still did not help.

I'm now leaning towards an electrical problem. The only thing on the electircal side that has been done is all 3 starter coils have been replaced and the distributor was switched from points to electric which fixed our pinging issue and the boat ran great. All of this was change before the current problem.

When attempting to bypass and hooking up a wire directly from the battery to the coil (the on stie mechanic recommended this to rule everything before the coil as a culprit) my father accidently tapped the jumper wire to the - on the coil and we heard a POP. After that we lost spark. We swapped to a spare coil and still have no spark. I checked and we have 12V to the coil but don't have continuity from the - on the coil to ground. I haven't had time to pull out the wiring diagram but noticed that wires from the - go to the ESA module. Do you think that might have been the POP? Also, I couldn't find a fuse on the + or - going to the coil, so is there some type of reset switch I'm missing?

Any help would be GREATLY appreciated.. I need to fix the lose of spark issue before I can even get back to the main issue..... This is my first inboard as my old boat had an outboard....

Thanks!

rule out the esa module by taking it out of the circuit and running just the ignition wire to the + side of the coil and the wire to the dist. to -.crank it over and check for spark.

 

[chrisc1024]

Re: 1988 3.0 OMC 2 issues

Thanks. The mechanic my dad talked to yesterday says that he most likely blew the shift assist module. He's already purchased a new one and we'll have it for this weeked if it is the culprit. If that's not it I'll follow the advice but don't I need to connect a ground to the - side if I remove the EAS? I looked throught the books and it looks like that allows the ground for the coil... I know byt putting a lead from the + of the battery to the + on the coil bypasses everything from the battery to the coil.... Right now we have NO ground to the - side of the coil.