470 Questions

J

jaysea

Junior Member
My 470 2 Barrel Carb 170hp Is Running Fine With No Problems,,,,,,,,i Have To Pull The Engine To Replace The Oil Pan ,,,,,,,,its Poris An Leaking For Years So This Is The Year,,,,,,,,so I Just Bought A Boat With A Complete 470 190 Hp For Spare Parts ,i Stripped It Of All The Drive Parts ,an Was Wondering If I Should Make Mine A 190 Hp By Changing The Intake An 4 Barrel Carb ,whats The Best Opinion Better Speed An Proformence ,or Leave It Alone ,thanks Jay
 
the 4bbl stuff is holy grail kind of finds. long block is identical, same cam, pistons, everything. If you use the 4bbl, make sure to include the oil cooler with it( they put it on those motors for a reason). I like the q-jets, the biggest problem I find is the throttle shafts wear out(they make a kit to fix them, but you better know your carbs). you should get better idle, acceration, and fuel economy(if you stay out of the secondarys) with the 4bbl over the 2bbl, especially if you have the merc carb, When you get it all back together, install a pertronix ignition(replaces the points), set the timing no higher than 5 degress btdc and ride. I allmost forgot, does your present engine have the 3" or 4" heat exchanger, if it has the 3", look for a 4" to replace it(hope your spare does)
 
a couple of other things you need to know, you may have to change the valve cover for the 4 bbl so the throttle cable will have the pivot point to attach to, you will probably need a longer cable also as the 4 bbl cable route comes around the back of the motor and cross the engine from the port side. Before you get to far inot it, have someone check the 4bbl carb out for you, if its junk theres no reason to go any futhur unless you want to spend the money on having the carb rebuilt or replaced
 
I am no Mechanic like spareparts is......but I have a 470 and have never had any problems with it. Mine also leaks oil like a siv. But I personally would change the oil pan and leave everything else alone. You go and put a 4 barrel on an old motor that is used to less power and your gonna blow somethin.:devil: Just my 2 cents.:zip:
 
there have been a couple of good points made, you have to excuse my enthusiasm for more power. Before you do anything, check the compresion of the engine, make sure you're not wasting money and time on a sick motor. the next thing is to inspect the exhasut riser and gasket, they are notorious for giving probelms, if you are going to swap manifolds, the exhaust would need it more than the intake. If you are happy with the performace of the engine/boat then only fix what is broken, if you feel the need for more power ,then consider swaping out the manifolds and carbs. If it ain't broke don't fix it, but if its slow chrome it
 
I've gotta 170 (470) also. Im with CY, if its running good, stay outta the hood! Changing the intake and exhaust would put undo pressure on the engine. For me I wouldnt change it. Maybe rebuild that 190 and keep for later use.
 
cfelton said:
I've gotta 170 (470) also. Im with CY, if its running good, stay outta the hood! Changing the intake and exhaust would put undo pressure on the engine. For me I wouldnt change it. Maybe rebuild that 190 and keep for later use.
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you got the original motor? any changes or major repairs? mine leaks oil like a champ, does yours?
 
Hey CY, this engine is the one that was in it when I bought it, not original to the boat. Its an 85-86 model 170. It had been rebuilt by Jasper but sat up about 5 years. I went through it again with new pistons, rings, brgs,head, riser ,ignition and I rebuilt the carburator. Runs great now!
 
cfelton said:
Hey CY, this engine is the one that was in it when I bought it, not original to the boat. Its an 85-86 model 170. It had been rebuilt by Jasper but sat up about 5 years. I went through it again with new pistons, rings, brgs,head, riser ,ignition and I rebuilt the carburator. Runs great now!
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DAM, YOU DID ALL THAT AFTER IT WAS REBUILT:oh:
 
Yep, the head had rusted out on the exhaust ports. So while I had it out and apart, I went through the bottom end and freshened it up a little. A couple of pistons had rust particals embedded in the tops. It had been bored .040 over. I honed the cylinders really lightly and put it back together. Everything looked good.:train:
 
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