Lehman 80 hp fuel in bilge blue smoke

Half way on my repositioning cruise from Galveston to to Tampa the starboard engine started to billow blue smoke. It never smoked before. The engine oil was checked and was several inches high. The oil was changed regularly on route after several hours and we made it to Tampa. The engine continued to run good the entire way. So I’m confused.

Now the question. I need to solve the issue. I have read it could be injectors, fuel lines, fuel lift pump. Stuck extra fuel button. Given the quick onset looking for help pinpointing the logical place to start and not just throwing money at wrong solutions.

Thanks to all in advance

Engine make, model, year, hours, etc
Ok Lehman 80

Pull rocker cover and look at fuel lines under the cover. Seen return rail fracture on these and it puts fuel in the oil.

Do not run the engine with that diluted oil in the sump, good way to wipe bearings. Drain oil and put in good oil before troubleshooting runs.

It’s a 1982 Lehman 80 about 3000 hrs

All of that plus are you changing the Sims oil at 50 hours?

I had everything serviced before I left engines including the sims oil and transmissions

Hendrik1 said:

I had everything serviced before I left engines including the sims oil and transmissions

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Could it be that the oil was mistakenly overfilled?

Ski in NC said:

Pull rocker cover and look at fuel lines under the cover. Seen return rail fracture on these and it puts fuel in the oil

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Agree. You can run w.o. rocker cover. Some oil might spill over on aft end. Nothing a paper towel can't handle. I would re-tighten all fittings. Note they are brass so don't torque them. Cracked line may not be obvious so use an LED flashlight and small mirror to check every inch.

Fuel pump is next candidate.They are inexpensive but a pain to replace. I would just replace it as a maintenance item.

Most likely cause of fuel in the pan in larger quantities is failure of the injector pump seal.