3.0 HO sluggish out of hole..??

Hello everyone!! I am excited to be a part of this wealth of knowledge found in these forums.. I am the owner of a 3.0 HO cobra with cobra stern drive.. The boat runs very well except out of the hole.. She is mounted up into a 1992 Forrester Diva 1800 GT, 18 ft.. It is heavy but the motor is rated at 140 hp.. i am getting close to max rpms at speed so i dont really want to put a smaller prop on.. When accerating from a stop i have to give it some then wait for it to catch up a little then give it some more.. seems like it just needs to get out of the water a little then i can accelerate further.. if i go past this sweet spot then it stayes bogged down and wont gain rpm's.. i bought the boat last year and have had the carb rebuilt, it is a 2 bbl holly.. there were some flakes on the brass screen of the inlet to the carb but other than that looked good but had it gone through anyway.. I am not sure if the carb is adjusted properly or perhaps the choke or advance are maladjusted.. I figured if i was getting WOT close to specs then it prob isnt the fuel as it is sucking more wide open then out of the hole.. I am rather new to the boating world and would like to get a direction before i throw a bunch of money at it.. thanx guys, hope to hear from you soon..

Re: 3.0 HO sluggish out of hole..??

Welcome to Iboats! What is that Max RPM? Are you sure it is your max? I'm leaning toward prop. If it truly is max RPM (& I'm not familiar w/Holley carb), there should be 2 or 3 holes in the accelerator pump actuator arm. You may try moving the linkage to the outer position (whole closest to end) of actuator arm. Other than that, if she is MAX rpm at WOT, there is only so much you can expect from a 3.0. If the boat is new to you, it may be holding water in foam / stringers. I have the same boat, except with a 4.3. My dry weight is 2100 (3000) including trailer. Yours should weigh similar. I used to own 19 ft Glastron with a 3.0 that I tuned very well, ran great. But it was very slugish pulling a tuber with a 19 pitch prop. Good luck!

Re: 3.0 HO sluggish out of hole..??

If it stays bogged on the hole shot with full throttle you are either over propped, or not getting enough fuel.
May also need a tune up.

Re: 3.0 HO sluggish out of hole..??

I think it sounds more like an engine/carb issue rather than a prop.
If you don't know carbs, then have someone that does look at it. I sounds like a fuel issue inside the carb. There are many tiny holes inside there and if one is blocked you will not get the best out of it.
If the carb turns out good, then plugs and such is probably in order.
You should be able to slam it WOT from an idle and it should not bog down or stumble.

Re: 3.0 HO sluggish out of hole..??

My WOT is about 4300 when I am alone and around 4100 when i am loaded up.. I think I am running a 15 by 17 prob.. and have a 15 by 19spare.. The specs give it a range of 4200 to 4600 so prob could go down a pitch or two.. i was hoping to maintain 35 or 40 mph on the top end.. I am leaning tword carb even though i had it rebuilt last year. ( which helped but did not solve the problem ) The fuil filter and pump was replaced last year, plugs allso.. outside of a carb problem i cant think of anything else.. compression checks out and all other systems seem ok.. I was thinking of looking further into the accelerater pump adjustment and other than that i might just go with a new holley carb.. it is around 290 for the new marine 2 bbl that holly offers in a 500 cfm.. How would she hold water in foam and how would that be removed..? I have never weighed the boat or trailer.. Even though the motor is only a 3.0, i can tell she has alot more to give.. thanx again for the advice guys, my local shop wasnt even interested in trying to solve the problem when i brought it to there attention.. after arguing with me over the fact that it had a rodchester instead of a holly i pretty much gave up.. so thanx again