4.3LX reproping?

[njw]

Hello,

I'm having an issue with my SeaRay 200BR and 1991 4.3LX. I re-propped with a 14.25x19 4-blade SS and I'm only getting 3600 RPM WOT when loaded and 3850 RPM when running solo. It seems like that prop should be OK from what I've read on this site, so now I'm wondering about the engine setup.

A new carb was installed prior to my purchase of the boat used. It is an Edelbrock 1409. The engine does bog briefly when the secondaries open, but seems to run great when on 2 barrels. After the bog, it seems to run ok on 4 barrels, but with no significant performance increase. The secondaries are set to open late - with the last 1/8 throttle travel.

Should I be able to turn this prop around 4400?

 

[Bondo]

Re: 4.3LX reproping?

Ayuh,... What was the prop, 'n performance Before ya reproped it,..??

 

[njw]

Re: 4.3LX reproping?

The problem is that I don't really know. It was a 5-blade SS prop. The shop I bought the new prop from *thinks* it was a 21 pitch (couldn't find any definitive markings). I was peaking about 4000 RPM, so they suggested the 19.

Is a 14x19 too much pitch or am I having power issues?

 

[EMC 1810SS]

Re: 4.3LX reproping?

You are having engine issues or the bottom is in bad shape. YOur 4.3 should be able to spin that 19 with NO problem. I think you need to get the carb dialed in before you go to far. Chances are, running correctly, it should spin the old prop to the proper rpm, or the old owners not have used it.

 

[njw]

Re: 4.3LX reproping?

So, assuming I have an engine HP problem, where should I start to look?
The engine starts fine and sounds fine when running. No misses or obvious
dropped cylinders. I thought maybe the tach is off, but 3600 RPM seems
to track with my speed (32 MPH) assuming a 1.8 drive and 15% prop slip.

When trailered and out of gear, the prop spins easily with no noise so at
least the final drive seems ok.

 

[Bondo]

Re: 4.3LX reproping?

So, assuming I have an engine HP problem, where should I start to look?

Ayuh,... I'd start with a complete Tune up, 'n Full service, along with a Compression test, myself...