Would it be worth it to switch to a 4 barrel carb on a new reman 4.3l merc?

[toolman4]

I have the option to get a 50hp increase with my reman block but I would have to get a 4 barrel carb and manifold. I think the heads I have are the vortec already because it is a 1999. Would the carb be set up ready and just put the new parts on and go? I don't want to blow it up again because of a carb change but the extra hp would be fun. For those that have done this could you feel the difference and was it worth it for the dollars spent? We ski and pull a three person tube with the 18ft bowrider with the 4.3 l merc in it.

 

[John_S]

Re: Would it be worth it to switch to a 4 barrel carb on a new reman 4.3l merc?

You need to understand where the reman supplier is getting the 50hp increase from. A 4brl and intake would only provide about 20hp on its own. Cam, different heads, what? But, whatever mods he is doing over stock, it is very unlikely that any marine 4brl will not need to be tuned for it.

To be safe, I would would want the reman to be the same engine spec as your stock one. Same heads, cam, and all major components. Sometimes they provide different components but claim the same overall performance. You will then be able to put your current intake and carb on it and should not have to retuned. Idle mixture, idle speed, and choke need to be done, but internal springs/jets/rods should be good. Make sure everything is good, run it for a season, make sure you don't have any warrantee issues.

Then, if you want a slight performance increase, re-consider an intake/carb change. It may get you 1-2mph more at wot, and a slight acceleration increase due to the smaller primaries.

 

[MCL]

Re: Would it be worth it to switch to a 4 barrel carb on a new reman 4.3l merc?

Im almost finished converting from a old 4.3mcm 2bbl to a reman 4.3 vortec with performer manifold,4bbl and alum manifolds,175hp--->235-245hp.But I have so much going on with my boat that it wont see water until next year.From all ive read its a very noticeable improvement,especially on smaller boats.

 

[toolman4]

Re: Would it be worth it to switch to a 4 barrel carb on a new reman 4.3l merc?

I think the 50 hp is bored over, and has some performance upgrades in the motor. I'll have to call to verify. The regular motor is also bored over but is supposed to have the same factory dimensions, crank, cam, etc. on the inside as mine. I can tune a carb, but are they close in what the settings will be? Thanks for the replys.

 

[John_S]

Re: Would it be worth it to switch to a 4 barrel carb on a new reman 4.3l merc?

The small increase in displacement for the over-bore, will produce negligable hp gain. You need to understand the mods they are doing. If they are just pushing the powerband up with a cam, your ability to pull a skier up, may be impacted. If you are going that way, your selection of a marine 4brl carb should probably be weighted toward a brand you are familiar with tuning. Otherwise, the Edelbrock 1409 is about as easy as it comes. It still takes time and testing. Rod and spring changes are easy. Top has to come off for jets. Even with knowing what the engine mods are, any answer about "how close" of a tune, is only a guess.

 

[sethjon]

Re: Would it be worth it to switch to a 4 barrel carb on a new reman 4.3l merc?

I have a 4.3 with a 4 bbl and can't imagine a 2 bbl. I think you'd feel a lot of difference and you wouldn't have to lean into the throttle as much.

 

[toolman4]

Re: Would it be worth it to switch to a 4 barrel carb on a new reman 4.3l merc?

Good info! I can tune 4 wheelers, snowmobiles, and such, but boats are new to me. I'll probably keep the 2 barrel and make sure she runs first, and then maybe switch to the edelbrock. If anybody else has done this 4 barrel conversion I would still like to hear your results. I am going to call the company Mon to see what they actually do to the motor to get 50hp.

 

[dsmmace]

Re: Would it be worth it to switch to a 4 barrel carb on a new reman 4.3l merc?

Buy the Edlebrock 1409 carb and get the matching intake manifold.

Install the 1485 jet kit and it should get it VERY close. I had to change the secondary jets up one size.