88 classic 50 bogs down under load

[yesterdaysyouth]

i was working on this motor and got it to run just fine in the barrel, took it to the river and it fell on it's face...

it will idle in gear all day long, maybe even 1/4 throttle... open it up and it will rev, start to plane the boat then it will bog down and die...

after we ran it like this for a while you could hear it missing, so i'm think it's an ignition problem. one or more cylinders loads up with fuel and bogs down the remiander???

i checked that the bowls were full of fuel after it died, also cleaned both carbs so i don't think it's a fuel issue.

i checked spark with an inline tester and had some spark on all 4 coils, not sure if it was real strong because the sun was so bright yesterday.

i've ordered new plug wires and already replaced the plugs...

anything else i should be checking? am i on the right course??
thanks
john

 

[zorak]

Re: 88 classic 50 bogs down under load

Start off with a compression test as the symptoms you are describing could be caused by that.Next verify you are running on all 4 cylinders. Google CDI troubleshooting and follow their troubleshooting procedures.You will have to build or buy a DVA adapter and get a digital VOM.Radioshack carries all the required parts for the DVA except a big enough capacitor.You can use one from an old flash unit or from a disposable camera. I have the same engine and it would start and run good but was only running on all 2 cylinders due to a bad switchbox. You might also check your fuel pump as they were never meant to handle alchohol fuels and the valves can deteriorate.It might not be pumping enough fuel to run any faster than you describe.I would put my money on the fuel pump and the rebuild is cheap but you need to check compression anyway to see what the overall condition of your engine is.

 

[yesterdaysyouth]

Re: 88 classic 50 bogs down under load

got the new plug wires on the motor today and took it for a ride....

first try it bogged down as normal, so i tried again and it took right off....

over and over, probally 15 times it did fine...

one more time it bogged down again, but i ran out of daylight and brought it home.

what do you think i should check next? I'm gonna go get a compression tester tommorow....

 

[yesterdaysyouth]

Re: 88 classic 50 bogs down under load

???