Looper Carb Question

[faztbullet]

Have 99 Model 225 . Have access to to some V-8 looper carbs. Have checked and venturi is way bigger than my 225 carbs, will swapping over to these make it a 250 or more, or will it be a bigger gas hog??
20' 401 dc javelin. 10" jack plate, 14.5 x 26 triton prop

[dynobo]

The 225 you have now is probably closer to 245 in stock trim. The big bore carbs will probably put you over the 250 mark but are much harder to "dial in" on a fishin boat than the stock units. If you are looking for dependability I would opt for the stockers. Those loopers are always looking for a reason to go lean, and you'll probably find one to give it. Just my opinion...........Bobo

[faztbullet]

This is stock motor with finger ports but does not have H.O port work. Would it be better to have exhaust ports cut to H.O specs?? I was told this would bump it to around 250hp.

[BenKeith]

Doubt you will notice any difference in the peformance of the big bore carbs over yours on a stock motor at 6,000 rpm. The biggest difference is going to be you will find your motor runs better in the midrange rpms with your carbs.

Adding HO exhaust ports will give you more hp (should do about the same as a 250/HO) but to do that the motor will have to be torn down, to big of a risk and getting grinding junk/shavings that don't blow/wash out in motor. You will also need to have the heads worked a little or plug the reliefs and run high octane to make up the compression loss since you will be raising the exhaust .080". The HO/250's have smaller relief holes.

If you tear it down to do the exhaust ports, just as well send it off to Stoker or one of other builders and have the whole block cleaned up and get about 275 hp.

Just remember, porting is only part of the job, getting the carbs dialed in so it makes the HP it should and not melt pistons, that's the major battle.

[faztbullet]

So.... If I have engine ported to H.O spec's , can I still run my stock 225 carbs and just up the main jets?? Will I need to run a electric fuel pump as I have heard that looper carbs dont hold enough fuel in bowls when jet size is over 80. I am just running a fuel pump ( aftermarket replacement for vro).

[BenKeith]

If your's is a 225, that's the same carbs they run on the HO and 250. Those are the same carbs I'm running on a motor that's probably putting out close to 300 hp.

If all you do is open the exhaust to HO specs, you should only need 74 - 76d mains and .102 pullovers. I've never been able to run larger than 78d's in mine but that will depend greatly on who ports it. Done right and it burns most of the fuel so it don't take those pipellines for jets. Done like most and then you need them, because it will be dumping a lot of it straight out the exhaust.

I don't have the PN but if you get the needle/seats for a 78 200, (used in lots of others also, just know those are the right ones) they have orfices approx .070" almost .020" larger than the stock seats and they will help keep from sucking the carbs dry. I've always run an electric pump but racer has said the stock pump is good to about 6,500 rpm, fuel side only, need to premix 100:1 oil if your still running oil injection for that rpm, it won't supply enough for that rpm.

I will say, I would not turn any looper over 6,100 - 6,200 rpm in stock form. The rods and pistons are usually so far out of balance, I sometimes wonder how they live like they do at 6,000.

If you want it to kick butt and live a long happy life, see if you can talk racer into doing the work for you. It's getting into boating season so he may be backed up until next winter but he can build you one kickass motor if that's what you want.

[lokinutz]

Ben, that PN for the large needle/seat is 396520. What kind of filter/fuel block/plumbing are you using with your elec pump?

[jphii]

lokinutz, here sre a couple of pics how mine is at the powerhead. I run a Holley red straight to the fuel rail. This is on the Seebold, not the race boat. Also have a glass filter before and after the pump.

[lokinutz]

Thanks for those pics. Thats just about how I was planning things. Did you stay with 3/8 to the block then 3/16 to the carbs?

[jphii]

Thanks for those pics. Thats just about how I was planning things. Did you stay with 3/8 to the block then 3/16 to the carbs?

That's it.