More than 4 adults....no plane...is it the prop?...is it the throttle?...what is it???

[brownja2]

Hi All,

My 4.3L OMC Cobra is in a 1989 VIP Vantage. The boat weighs 2500 pounds and says it has a max. load of 1200 pounds, persons and gear. The problem is that it runs just great and gets right up on plane UNTIL, There is more than 4 adults and a cooler and other gear. I am guessing all together I have maybe 900-1000 pounds on the boat when it starts to not get up on plane anymore. Is this normal? It seems like a 6 cylinder 4.3L would still be able to get up and go with that load on it! I have read other posts saying this could have to do with the prop? Also, it seems like I have to have the throttle about half way down before I get any response and start to go any faster. Maybe the throttle cable or linkage needs adjustment? Any ideas??

 

[bondo]

Ayuh,... It Could be alota things,...

A Tune up, service, 'n Compression test will give ya a baseline to work from...

 

[corsair23]

Trim Tabs? Try some " Super Tabs ". They're the spring-loaded ones that adjust automatically. I have been seriously thinking about them on my old gal.....

I priced them locally with the 120 pound springs ( 20 foot 2750 pound Boat) for $200 Canadian, taxes included!!! Owner installed, very easy to do. All you need is a pencil, and a drill.