Ignition and prop Questions

[ruben]

Hi Guys,

I have an 87 Four Winns 170 Horizon (17ft) OMC
It has a 2002 4.3L out of a Chevy Blazer. Edlbrock 600 carb and a Edlbrock performer manifold.(rated at 190hp at 4400rpm --250lbs tq at 2800rpm with efi in the blazer)

It actually runs a bit better than the original 205hp that was originally in the boat.

First Question: at 100 degree day with 3/4 tank of gas and 700 lbs of people in the boat, it has a very hard time getting me out of the water(200lbs) on a single ski. top speed is 44mph at 4300rpm with 900lbs of passengers.the prop is a 14 1/2 x 19.

What is your recommended prop to get a skier up with this much weight in the boat?


I figured out my ignition question
thanks

[ruben]

Anyone!!

[alex fletcher]

ruben the way I see it is You and the Boat Both start to plan at the same time
so we have to look at the Prop as more of a displacement Prop then a planing Prop.meaning it would be flatter with very little cupping Do you own a small angle grinder? or see a pro. if 4300 rpm is the boat top speed unladen you are over pitched

[ruben]

thanks for the reply Alex.

Im not really sure of the actural rpm of the engine.

at 42mph the boat tach says 5200rpm. and my MAC Tools multimeter says 4000rpm.

what should the rpm be at 42mph with this prop and 1.84 gear set?


Now with 2 people in the boat it will go 48-50mph or so.

but most of the time I have 4-5 people in the boat when we ski.

Yes I have a grinder.

thanks

[Jango]

With about 10% slip, 42 MPH with a 19p. cupped prop your RPM will be 4500 - 4550. If 4 people will be the norm when you Ski. I would suggest a 4 Blade prop. You may have to drop 1" of pitch with the 4 blade.

[alex fletcher]

Got to say with 4-5 people and a skier you must be close to over loaded six in a 17 ft boat can I suggest a larger boat Even so Jango's right 4 blade may be the way to go but you may have to drop 2 inches in pitch and throttle back when not skiing and you will lose a knot or two

[ruben]

what do you think of the hinged devices that you bolt to the outdrive to help it get on plane quicker?

[alex fletcher]

Foils, trim tab or wings wont do a thing, you have to address the fundamental problem, loaded up the Boat bogs down due to to much whight. Either lighten the boat, get a bigger engine, or reduce the pitch of the prop, or increase the gearbox reduction ratio.
sorry but I think that they are your only options

[stonebreaker]

You might try a different launch technique when you slalom, too. When I was younger, we skied behind my dad's bass boat. The boat was fiberglass, 18 feet long, with an 85 hp outboard, and barely managed 30 mph when pulling a skier. I found that I was able to get up on plane much quicker and with less fatigue in my hands if I bent my knees and stayed as close to the ski as possible, putting as much weight as I could over my front foot and even pulling up with my back foot to keep the ski as parallel to the water's surface as I could. This kept more of the ski in the water, which meant that I would get up on plane that much quicker. It was a little awkward at first, but once I got up to speed I could ski a lot longer before my hands got tired.

Another technique we used when we got bigger was stretching out the rope, then turning the boat 90 degrees before we launched. It was REAL hard to learn that one, but it let the boat get going before having to pull up the skier, and it didn't yank you over on your face like it would if you started with a slack rope.

[gonzo]

If you have a motor right out of a truck, the camshaft, timing and other parts are incorrect and will never give you the low RPM torque you need.

[stonebreaker]

If you have a motor right out of a truck, the camshaft, timing and other parts are incorrect and will never give you the low RPM torque you need.
Are we going to have to go through this again? The truck cam makes more torque than the marine cam below 3000 rpm. Marine engines are not the be-all and end-all torque monsters you seem to think they are. Look it up on www.gmpowertrain.com and please verify your info before you go spouting bad info all over the forum again.

Hell, I'll post the links for you. Straight from the manufacturer.
marine engine (http://www.gm.com/automotive/gmpowertrain/engines/specialized/marine/2006_4300_marine.pdf)
truck engine (http://media.gm.com/us/powertrain/en/product_services/2007/HPT%20Library/Gen1eV6/2007_43L_V6_LU3_Silverado.pdf)

[ruben]

Originally I had a roller cam 2bbl motor that I put on an edelbrock 4bbl and manifold.

Now I have this 2002 injected vortec headed engine out of a blazer that I put a edelbrock manifold and 4bbl on.

The new motor pulls better all the way around, even though the cam is smaller.
Due to the vortec heads.

I wonder how it would run with the roller cam out of the original motor?

does anyone know if the 2bbl roller cam is the same cam as the 4bbl roller cam in the earlier OMC engines?

[mattcat79]

ok does any one know why my trailer trim up buttons when pushed stay on and wont shut off unless i disconect the battery. cuold it be the cylinoid. thanks

[ruben]

Matcat79,

You should have posted your unrelated question in a new post(new thread)

You probably will get better response that way

[gonzo]

Stonebreaker is a computer geek(by his own description) that doesn't even own a boat. He does find all kinds of links to manufacturers which he claims, in other threads, are not to be trusted.

[stonebreaker]

Stonebreaker is a computer geek(by his own description) that doesn't even own a boat. He does find all kinds of links to manufacturers which he claims, in other threads, are not to be trusted.
Yeah, those computer geeks know nothing about motors! Gee, I wonder how he got his 96 impala ss to run 11.9 at 115 mph in the quarter mile on pump gas and without stripping the car down? You'd think a computer geek wouldn't have enough common sense to know how to install his own cam or port his own heads.

But he does. :P Go figure.

[stonebreaker]

Originally I had a roller cam 2bbl motor that I put on an edelbrock 4bbl and manifold.

Now I have this 2002 injected vortec headed engine out of a blazer that I put a edelbrock manifold and 4bbl on.

The new motor pulls better all the way around, even though the cam is smaller.
Due to the vortec heads.

I wonder how it would run with the roller cam out of the original motor?

does anyone know if the 2bbl roller cam is the same cam as the 4bbl roller cam in the earlier OMC engines?
The optimum cam design is closely dictated by your head specs. I doubt the earlier cam would work much better than the stock one. If you follow the links I posted above for the power curves for the truck and marine versions of this engine, you'll see that the marine cam gives up some torque down low in order to gain some horsepower higher in the rpm band. Unless you change your prop, this is only going to make your hole shot worse, of course. Once you do, though, the higher revving marine cam should give you most of your top end back. Knowing how much R&D GM puts into their powertrain products, I'd say at a guess it's probably going to have better overall performance than the truck cam once you get your prop issues sorted out.

If you're going to change cams, you might look at this (http://www.cranecams.com/?show=browseParts&lvl=2&prt=5&Vehicle_Type=Auto&Cylinders=6&Engine_Make=CHEVROLET&Year=2002&Engine_Size=4.3%20L&partNumber=1439721&partType=camshaft) one. I'm running the V8 version of this cam (same grind, just two more cylinders) in my iron headed LT1 impala and it works incredibly well. It idles so smooth at 650 rpm you'd never know there was a hotrod cam in the car - yet it pulls all the way to 6000 rpm, and the car still gets 22 mpg on the highway. Passes the tailpipe sniff test, too.

[ruben]

does anyone know if the 2bbl roller cam is the same cam as the 4bbl roller cam in the earlier OMC engines?


BTW I changed the edelbrock 600 with a 500 and as I thought would happen, it gets out of the hole much better.
Will have to try and slalom behind it now.

With a lot of people in the boat it now gets on plane in about 3 seconds.( counting one one thousand- two one thousand- three one thousand..)

however it lifts the bow of the boat pretty high initially, and has to overcome this.(putting 2 people on the bow helps of course)

top speed now with the 500 carb is:

fully loaded -45mph

2 people in the boat- 50mph

(had to jet the carb richer for boat use.)

[gonzo]

Seeing is believing. Since it is the season for drag racing, tell me where and when you are running your car and I'll be there.

[stonebreaker]

Seeing is believing. Since it is the season for drag racing, tell me where and when you are running your car and I'll be there.
I can do better than that. Here's a whole mess of impala ss timeslips. I'm #49 on the list, as well as #102. (http://dan.esteban.com/impalass/ReturnTopET.asp?SelectedClass=1&Sort=) Every car on this list is either a 94-96 impala ss or a caprice, and there are even a few buick roadmasters and a fleetwood or two. I'm not even close to what some of my more dedicated friends have done.

We know our stuff. You better recognize, b.

[gonzo]

Those times are not super impressive; about average for the type of car. It doesn't mean you did any of the work anyway or that you can drive it. For that matter that you own the car. Tell me when you race and I'll show up.

[Frosty]

In the 70s I had a big American type ski boat with a mercruiser 228--it was a very poor pullout for skiing. I changed props,messed with carbs, all sorts of stuff, untill one day the Yankee motor parts man said put in an Edelbrock 2001 intake manifold ( I think it was )for 4 wheel drive vehicle?? Well they were 99 pounds and I couldnt afford it. Finally I bit the bullet and bought it.

Man-- that was the best 99 pounds I ever spent. I just could not believe the extra torque --possibly 25% increase over your wonderfull so called marine manifiold.

He wanted me to fit the cam and manifold package, I was qite happy with the manifold!!!.

[gonzo]

Those high rise manifolds are great if you have the deck clearance. Volvo makes an intake very similar to the Edlebrock but with brass inserts at the water passages.

[stonebreaker]

Those times are not super impressive; about average for the type of car. It doesn't mean you did any of the work anyway or that you can drive it. For that matter that you own the car. Tell me when you race and I'll show up.

Gateway raceway in St. Louis. (http://www.gatewayraceway.com/) Tuesday night, August 15. Bring your pink slip.

BTW, this doesn't distract me from the fact that the 4.3 truck cam makes more torque below 3000 rpm than the 4.3 marine cam.

[ruben]

I went out yesterday and skied behind the boat with the boat fully loaded as it was previously.

Absolutely no problem at all getting up.

The difference between the carburetors was amazing.


Also,
I have a set of the older style 4.3 heads with edelbrock intake if anyone is interested.

The heads have less than 3 hours on them since a complete valve job with 2.02 x 1.60 stainless valves was done.

The intake also has less than 3 hours on it.

Im in California

[stonebreaker]

does anyone know if the 2bbl roller cam is the same cam as the 4bbl roller cam in the earlier OMC engines?


BTW I changed the edelbrock 600 with a 500 and as I thought would happen, it gets out of the hole much better.
Will have to try and slalom behind it now.

With a lot of people in the boat it now gets on plane in about 3 seconds.( counting one one thousand- two one thousand- three one thousand..)

however it lifts the bow of the boat pretty high initially, and has to overcome this.(putting 2 people on the bow helps of course)

top speed now with the 500 carb is:

fully loaded -45mph

2 people in the boat- 50mph

(had to jet the carb richer for boat use.)
Glad to see you solved your problem. However, everyone on this forum has been telling me that automotive carbs are a fire hazard on boats, because of the fact that boat engine compartments can't vent spilled gas the way a car can, and marine carbs have a different design to make them safer.

As far as the '87 4 barrel cam, I seriously doubt you would see any improvement in performance by swapping it out with your current cam. There has been a HUGE amount of research done in the last 20 years in cam design, what with CAFE and all. In particular, I suspect your current cam probably has higher lift, less valve overlap, and shorter duration than the older cam. All of these things make it a much better performer below 3000 rpm, right where you need it with your heavy boat, and the higher lift makes up for lost duration at higher rpm.

[ruben]

the only difference in venting was a single tube coming from the top of the secondaries. Which I drilled on the other carb, now they vent the same.

peak torque on this motor is at 2800 rpm, but when I throttle it, it goes right past peak torque to around 3200 rpm or so.

Maybe even a tighter prop would work better with this engine.

Now peak torque at 2800 is with the factory efi. With my carb setup, im sure peak torque is at a higher rpm.

[stonebreaker]

Yeah, I remember them saying it had to do with venting. I'm not much on carbs myself, all my hotrodding has been with fuel injection. We had a time of it a few years ago trying to make the old heads understand that the size of the throttle body doesn't affect the fuel mix the way a carb's throat size does. You just have to reprogram the fuel injector and transmission line pressure tables in the engine computer to reflect the different flow numbers of a bigger throttle body and/or different injectors.

Have you thought about swapping to a bigger cam and running Rhoads lifters to keep the bottom end?

[Frosty]

With my automotive background its,---- well pathetic that I have never been to a drag strip. St Louis is a bit far for me to go ( dont even know where it is) but I wish I could go as well. I would enjoy something like that so much I --I --might even buy the beer, yes i will buy you one too Gonzo, but not for Stonebreaker though-- hes driving!! I suppose it will be that crappy Budwieser stuff,-- whats a pink slip?

[stonebreaker]

With my automotive background its,---- well pathetic that I have never been to a drag strip. St Louis is a bit far for me to go ( dont even know where it is) but I wish I could go as well. I would enjoy something like that so much I --I --might even buy the beer, yes i will buy you one too Gonzo, but not for Stonebreaker though-- hes driving!! I suppose it will be that crappy Budwieser stuff,-- whats a pink slip?
Come on down - after we drag race, we can tour the Budweiser brewery and get the beer for free!:D A pink slip, btw, is racer slang for the title of your car. I suppose because back in the day they were printed on pink paper or something.

PS - don't go to the drag strip unless you're looking for a new hobby to pour money into. It's worse than boating - you can bracket race in the sportsman class all night for 20 bucks at most places; but then you get tired of being the slowest guy at the track, and the mods begin...

[Frosty]

Ahh ok,-- I saw that in a movie once where two guys draged for the ownership of the car. So you want to drag with Gonzo and take his motor?

I would immagine that gonzo would drive a-- Mmm lets see some thing a bit wussy-- maybe a VW Golf or a Volvo station wagon-- with a dog in the back.

How will you recognise him, will you wear a flower in your lappel or hold an umbrella. I will be wearing a toilet seat around my neck. This always makes me stand out from the crowd, unless of course this is common practice at American drag strips.

Sounds like I need to bring some decent beer as well.

[stonebreaker]

Ahh ok,-- I saw that in a movie once where two guys draged for the ownership of the car. So you want to drag with Gonzo and take his motor?

I would immagine that gonzo would drive a-- Mmm lets see some thing a bit wussy-- maybe a VW Golf or a Volvo station wagon-- with a dog in the back.

How will you recognise him, will you wear a flower in your lappel or hold an umbrella. I will be wearing a toilet seat around my neck. This always makes me stand out from the crowd, unless of course this is common practice at American drag strips.

Sounds like I need to bring some decent beer as well.
Nah, there's actually some pretty good brew pubs (http://www.beertravelers.com/indexes/wateringholes/st-louis_pubcrawl.html) downtown.

[gonzo]

Sorry Stonebreaker, but besides having no knowledge of the difference between automotive and marine applications you are a bad liar. The time slips show you are running nitrous;hardly justifying your claim of a street car. Also, for a nitrous application, the times suck.

[gonzo]

I found more of Stonebreaker's lies. In the information from the race track it shows that all the mechanical components and the porting etc. was done by real professionals at speed shops. His claims that he did anything is all hot air. I quote:
"LT1 355, built by Kenson Automotive in Fairfax, VA. These guys machine the engine blocks for Autothority, the BMW and Porche tuners. PCM by Bryan Herter" "In addition to the usual stuff, 150hp TNT nitrous system, additional fuel pump in the tank." "4L60e built by Briscoe Transmissions in Woodbridge, VA, 3500 stall Super Yank converter 3.73 gears" Next time you insult a real grease monkey who turns wrenches for a living and for a hobby don't lie. I guess as a computer geek you plays with your mouse instead.

[stonebreaker]

I found more of Stonebreaker's lies. In the information from the race track it shows that all the mechanical components and the porting etc. was done by real professionals at speed shops. His claims that he did anything is all hot air. I quote:
"LT1 355, built by Kenson Automotive in Fairfax, VA. These guys machine the engine blocks for Autothority, the BMW and Porche tuners. PCM by Bryan Herter" "In addition to the usual stuff, 150hp TNT nitrous system, additional fuel pump in the tank." "4L60e built by Briscoe Transmissions in Woodbridge, VA, 3500 stall Super Yank converter 3.73 gears" Next time you insult a real grease monkey who turns wrenches for a living and for a hobby don't lie. I guess as a computer geek you plays with your mouse instead.
Yeah, having the block machined at Kenson seemed like the smart thing to do - putting a CNC machine in my garage just wasn't cost-effective. :rolleyes: You, on the other hand, got busted spouting wrong info to a forum member AGAIN, after you'd been warned. THAT's what matters. Throwing dirt on me doesn't do you any good, because it's not my word against yours. It's your word against GM's.

Tell you what. After I take your car on Tuesday, I'll even let you take first swing at me. I'll get my buddies to video and we'll post it to the forum.

[gonzo]

You didn't just get it machined but the engine and transmission are completely built by real professionals. Stonebreaker, you got caught in your lies. Bluster and offers to swing at you won't change the shame of it. What are you, nine years old? Maybe all these years of playing with your mouse( probably the one eyed one, has made you believe that real life is like video games.

[stonebreaker]

You didn't just get it machined but the engine and transmission are completely built by real professionals. Stonebreaker, you got caught in your lies. Bluster and offers to swing at you won't change the shame of it. What are you, nine years old? Maybe all these years of playing with your mouse( probably the one eyed one, has made you believe that real life is like video games.
Where did I say I completely built my own engine? All I said was that I ported my own heads and installed my own cam. I DID make sure my rings were a little tighter than 80 thousanths, though.

[extremebase]

HA HA HA HA...this is great...I guess the first thing I will say is I'm an import guy into tracks (EESCC, PIR) and starting to get into drifting...I'm no super mechanic, but I do turn wrenchs for a living....

as far as your fight goes, I went over all the info just for the hell of it, I know realize that stonebreaker really thinks he is tuff, and also thinks he is a good lier! (Just because you didn't say doesn't mean you didn't lie...its what you didn't say!)

Running NOS!!!! come on, if you get a car worth a **** you don't need that crap. My car is set for a track, and it will do a 11.7 with no NOS. Yes it has the turbo, but only one and a 16g so I am out of boost before I know it. Anyway keep the fight going I'm loving it...I just came here because I know jack crap about marine motors and not much about domestic anyway and so I know nothing about my boat...except for the fact it is not running right!

Hey gonzo...you have any idea why on my 4.3L V6 Chev in my sea ray dies when I put it in gear??? I am guessing carbs...but as mentioned I don't know carbs...I know Feul Injection...maybe you can help me out..

[gonzo]

If it is a Mercruiser, there is an interrupt switch in the shift cable. It is usually installed in the starboard manifold riser. When you shift it momentarily kills the ignition to ease the gears in and out. If the cable to the drive or the switch are sticking it will kill the motor.

[extremebase]

so How do I fix that problem? any idea were to download a book on this motor?

[gonzo]

Clymer and Chilton make manuals for it with good pictures and explanations. They are easily available at most bookstores, boat dealers or online.