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Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3372
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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We have a 430 SeaVee which has 4 300 4 strokes 2013 models.

Customer Question

We have a 430 SeaVee which has 4 300 4 strokes 2013 models. When coming in from offshore yesterday, I noticed the outside starboard motor about 200 rpm less than others. I stopped, put in reverse and took off again. Motors were all within 100 Rpm of each other. Ran in another hour and when we shut down to enter harbor, low oil pressure alarm came on, on same motor. Shut that engine down immediately. Docked and waited almost an hour, checked oil level, everything good and started back up. No alarms of any sort. Ran at differed rpm for about 20 minutes and did not hear any abnormal noice and never seen the alarm. We plan on going offshore this afternoon and we have a 180 mile ride home. Any suggestions?
Submitted: 6 months ago.
Category: Boat
Expert:  Charles replied 6 months ago.

Hello, my name is***** will assist you.

The motor could have been getting hot from something that was blocking the water inlets partially. This would cause the oil to get hotter and thin out, thus giving you the alarm. Keep an eye on your drives if you are running weed lines, as it can clog the water intakes and then overheat your engines.

Customer: replied 6 months ago.
No heat alarms. We have Yamahas, not mercury's. Not sure you really addressed my question. Please read over what I sent and reply again
Expert:  Charles replied 6 months ago.

Yes, I read the question several times. I work on all brands, not just Mercs.

Since engines all are different internally, you will have some difference in RPM at the same throttle setting. 100, or even 200 is about normal.

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