4.3L Mercruiser Alpha 1

[moser42]

Ok this is what I have:
-2006 Four Winns 190 Horizon (19ft)
4.3L Mercuiser 190hp with Alpha 1 outdrive
It only has 27 hours on it and I have changed the oil once after the first 10 hours, then once while winterizing it last fall.
I've had it on out for three rides this year, good long runs down the lake and back. On my last ride I decided to open it up and was disappointed.
At WOT it turned 4200 to 4250 rpms and it says on the motor max rpm is 4400 to 4800 which it did last year, I saw 4700 rpms last year.
It topped out at about 43mph and it did 48-49 mph last year.
How can it slow down this much?

Everything else on the motor looks fine except the drivelube monitor is below the add line. What lube should I put in that container, Merc hi performance drive lube for the Alpha 1? Should I change the gear oil before filling this container?

Thanks alot!!!!

 

[Haut Medoc]

Re: 4.3L Mercruiser Alpha 1

I'd change the gear lube & look for signs of water intrusion.....
Though it does seem awfully new for such problems......
Still....It really should not lose anything level wise......
Changing the gear oil is something that should be done once a year as part of preventative maintenence.....
What, if any, preventative maintainence have you performed this season othere than changing the oil?......​

 

[John_S]

Re: 4.3L Mercruiser Alpha 1

Assuming you had the drive trimmed the same, the boat was loaded similiar, and no bottom growth, and no prop change, you should be much closer to last years rpms. That is a significant difference. Like suggested, drive lube should be replaced yearly, along with lube monitor bottle clean out. Unless you see something disturbing in the oil, like allott of fine metal particles or water, unlikely the drive is causing the rpm loss. If you didn't during your fall winterization or spring comissioning, change your fuel water seperator/filter. If a carbed motor, may want to check inlet fuel filter and throttle linkage for full opening. Also, cover the basic tune-up stuff, if not already done, plugs, timing, dist cap & rotor, cleaning flame arrestor, etc.

 

[180shabah]

Re: 4.3L Mercruiser Alpha 1

I second the following:

If you didn't during your fall winterization or spring comissioning, change your fuel water seperator/filter. If a carbed motor, may want to check inlet fuel filter and throttle linkage for full opening. Also, cover the basic tune-up stuff, if not already done, plugs, timing, dist cap & rotor, cleaning flame arrestor, etc.

 

[moser42]

Re: 4.3L Mercruiser Alpha 1

It was the same conditions as last year: the boat is kept on a lift so no bottom growth, trimmed the same and with the same prop, loaded with just me in the boat and a very calm day on the lake. This is why I thought it was not performing to its max.

The boat is on the boat lift at my camp, I'll go to check it tomorrow or thursday, clean the flame arrestor, check throttle linkage, give it a tune-up and change the drive lube too. If that doesnt work then I don't know what to do, maybe i should bring it in to the dealer and get them to fix it on warranty.
What drive lube should I use in the alpha 1 drive?
When I change the drive lube, well the monitor container empty out too? and do I fill up the container after the drive is full of lube again? or before I fill the drive?

Thanks, any other suggestions for why it might be losing power would be appreciated! thanks alot for all the help!!