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climbinggod
12-27-2007, 09:39 PM
Hi there,

I have learned alot from this site already. I bought my 1st boat, a '92 prostar 190 back in the summer, had an absolute blast with it. It is now winterized in the garage. I am going to tinker with it over the winter.

I have a few questions. First with the engine. I have found 3 sending units on the engine, the oil pressure sender, I think the water temp sender on the drivers side, and what I believe to be a water temp switch on the left side, maybe going to a buzzer on the dash???? I was wondering if this switch on the left side is what I think it is and also is there an oil pressure switch which turns a buzzer on the dash with low oil pressure. No buzzer just with the key on.

With the transmission I think it is the neutral safety switch on the drivers side but there is also a switch on the top that I have no clue about. There is no trans temp gauge on the dash.

I was also wondering what carb I have, other than I know it is a Holley. It has a solid steel line going to it then branches off to 2 sides of the carb. What model is this???

Sorry I did take pics but I can't find the cable to download them :mad:

Any help is greatly appreciated.

TMCNo1
12-27-2007, 09:53 PM
4010 is dual line like you apparently have that has a split line going to the front and rear bowl on the drivers (starboard) side. This carb can be as troublesome as a redheaded stepchild.

4160 is the is a single line going to the observer (port) side of the front bowl. A very efficient and mostly troublefree carb.

climbinggod
12-27-2007, 10:13 PM
Thanks for the info, I did have a few problems and was thinking of changing it out for a 4160. Mine is a manual choke, cycle the throttle lever forward to reverse to set it. Can I get a 4160 manual choke and what cfm should I be looking for?? I have the Indmar 351 engine.

east tx skier
12-27-2007, 10:31 PM
From my experience with the 4160 versus the 4010, I think you'll be very pleased with the upgrade.

climbinggod
12-27-2007, 11:52 PM
Just been looking around on the net and found this Holley 4160 Carb. Is the black bit on the side with the 2 electrical terminals the ELECTRIC choke mechanism??? Cos that is what mine has. I thought mine was a mechanical choke, guess i was wrong.

ProStar Slalom
12-28-2007, 06:29 AM
Yes, that's the electric choke on the side. I bought a new 4160 for my 87 last summer (didn't want to mess with a rebuild kit). Just bolted it on and turned the key...didn't even require an idle adjustment...best $400 I spent all year.

WTRSK1R
12-28-2007, 08:54 AM
Thanks for the info, I did have a few problems and was thinking of changing it out for a 4160. Mine is a manual choke, cycle the throttle lever forward to reverse to set it. Can I get a 4160 manual choke and what cfm should I be looking for?? I have the Indmar 351 engine.

Even with an electric choke, you still need to push the throttle once to "set" it. Not sure how long you have been driving, but back in the carb days the first thing you had to do with a car in winter was mash the peddle down once to set the choke. The carb on a boat is exactly the same. It takes the first push to allow the linkage to drop the choke plate in place. Once you are running, the electric choke will reduce the tension on the choke spring as the engine warms up. This reduced spring tension allows the choke plate to open back up.

TMCNo1
12-28-2007, 09:37 AM
Even with an electric choke, you still need to push the throttle once to "set" it. Not sure how long you have been driving, but back in the carb days the first thing you had to do with a car in winter was mash the peddle down once to set the choke. The carb on a boat is exactly the same. It takes the first push to allow the linkage to drop the choke plate in place. Once you are running, the electric choke will reduce the tension on the choke spring as the engine warms up. This reduced spring tension allows the choke plate to open back up.


I like that explanation! You said it well, I'll have to remember that for future reference.

climbinggod
12-28-2007, 03:50 PM
man you guys are awsome

Hunterb
01-03-2008, 04:44 PM
I don't think that's actually how the choke works on that carb, when installed on a boat anyway. With an electric choke on a vehicle it is necessary to step on the gas pedal to set the little stepped plate that holds the throttle open slightly to aid in warming up the engine. The choke plate on a marine carb will close fully regardless of whether you push on the throttle in advance or not. Marine applications of the 4160 carb do not use the stepped plate to hold the throttle open. You'll notice with a boat that, if you want a high idle during warm-up, you have to push the throttle slightly. Also, interestingly enough, the choke does not close in response to the engine temperature. It has its own internal mechanism that causes the plate to open gradually. You can see this in action if you simply turn the key on with the engine cold, the choke plate will close fully and then gradually open whether you start the motor or not. The idea with marine applications is that you do not want to have a high idle during warm-up or if you do, you have to push the throttle slightly and then you can't put it in gear. In order to put in in gear you must put the throttle back to idle. The marine industry considers it safer that way because you don't have people ramming docks and other boats etc. by putting their boats in gear with the engine running faster than idle.

I'm not a carb expert by any means and I only know this because when I first got my boat I thought someone had removed the stepped plate etc. from the choke mechanism so I called Holley to order the parts. After a lengthy discussion with them I now understand how the choke works (on a 4160 anyway) and why it is set up that way. The electric choke works very well so I would not bother with a manual choke and definitely do not put the stepped plate in there to hold the throttle open.

Hope that helps.

Bruce

learjet2230
01-03-2008, 04:49 PM
Spot on Bruce!!

mayo93prostar
01-03-2008, 05:01 PM
the other sender on top of the tranny is an overtemp sensor for the tranny. there should be a light on the dash for it. I have a 93 prostar with Indmar ford 351 that has this. you are correct that the one on the side of the tranny is the neutral safety switch. welcome to the site. www.skidim.com is a good source for parts and give them a call for technical support. they are good people. what tinkering are you planning on doing? I have the redheaded stepchild 4010 carb and plan to do a rebuild this winter. It is leaking into the intake when I shut it off causing the engine to flood when hot.

learjet2230
01-03-2008, 05:17 PM
sounds like a needle and/or seat or float set too high!

climbinggod
01-03-2008, 07:20 PM
Hi there Hunterb, So I quote "The choke plate on a marine carb will close fully regardless of whether you push on the throttle in advance or not." Now that is very interesting I and alot of people on this forum thought that you had to fully engage the throttle lever to set it. Having said that it would mean that when you turn the key to the start position, it would set the choke then, right?? What about if the engine is allreay warm what would prevent the choke being set every time, after you shut the key off?? I will have a look at it next time I have the battery in the boat. Cheers

Chas
01-03-2008, 07:33 PM
In my experience, the design keeps the choke from closing during all of those stop and drops that we do with our boats.

Inside that black housing is a standard bi-metallic spring like any other choke. But it has an electric heater which warms it up to open the choke. Once everything gets hot, it stays open with our without the juice to the heater.

Hunterb
01-03-2008, 08:46 PM
Hi Climbinggod,

Yes that is correct, when you turn on the key the choke will close provided it is cold. As Chas said there is a heater in the choke housing that heats the spring which causes the choke plate to gradually open. If you run the engine until it is warm and then shut it off for a while the choke may cool off enough for it to close again when you turn the key back on but it will open very quickly. If you look at a stock marine 4160 you will see that it has no stepped plate installed so the choke plate and the throttle are completely separate. If you think about it in terms of the old 'road vehicle' carbs that use the stepped plate what you were doing when you stepped on the gas prior to starting was bumping the throttle up so the engine would idle higher without your foot on the gas. When the engine was sufficiently warm you would 'disengage' the stepped plate by briefly somping on the gas. This was really the only way to disengage it. I have never seen a marine motor set up so that you had to jump on the gas to disengage the choke and that's because the two are not connected. I would find it a little disconcerting to be putting my boat in gear with the engine idling high as well.

I realize people are often confused about this and, as I said, I am far from a carb expert but I have researched this particular problem quite a bit. I would think that if you look at your carb you will see that there is no stepped plate and therefore no connection between the throttle and the choke. Definitely when you get the battery back in the boat take the spark arrestor off and turn the key on. If your choke is working properly it will be closed. Do not start the motor. If working propelry, the choke will gradually open. It should take a couple of minutes. The rate the choke opens is adjustable and I can tell you how to do that if you want.

Given your location (the wrong side of the Rockies) it may be a while before you have a battery in the boat

mayo93prostar
01-03-2008, 09:31 PM
sounds like a needle and/or seat or float set too high!

lear, yep, I expect it is what you said. I may try to just adjust this before doing whole rebuild. it runs like a champ when first start and after get it started when hot.

relative to the "pump the throttle discussion" going on. I know fuel gets pumped into the carb when you push the throttle all the way forward so some that may think they are "setting the choke" are actually just pumping some fuel in so it starts.

Hunterb
01-04-2008, 12:23 AM
Whoops, sent that last reply before it was totally finished.

May087 is right on. Pumping the throttle prior to starting causes the accelerator pump to shoot fuel into the carb. Many people find it helpful to do that even when the motor is warm.

Good luck with the boat !!! Hope it's not too cold in Calgary. I'll be passing though in a couple of weeks.

Bruce

climbinggod
01-04-2008, 12:52 AM
Thanks for the info guys, My boat is winterized in my garage right now and I am planning to do lots on it this winter. Just got the boat last summer (1st ever boat) and would like to get to know how everything works, being a mechanic for Bobcat. What better way than to rip it all apart and rebuild. I will be doing a full service and tune up (oil change trans and Eng Cap, rota, plugs Etc, ripping the dash out and rewiring grounds, etc ( already found a bunch of loose grounds). Changing the impeller and thermostat, putting in a buzzer and "Idiot light" for the trans temp, water over temp and low oil press. Changing the heater fan speed from med to high. Fixing the stereo, Replacing the old 4010 for a 4160. I have lots to be getting on with better get to work. LOL.
Cheers All.

FYI weather here now is a warm +3 c (It's Chinooking right now)

Roll on June 2008

mayo93prostar
01-04-2008, 07:30 AM
climber, I recommend you pullout the back seat and pull up the rear center floor board to grease and check the steering cable, rudder, and the drive shaft alignment. If you search on here for shaft alignment you will find instructions on how to check this. Plus this gives you the opportunity to get to know the boat even better in this critical area back there. I did this and most of the stuff you talk about last winter after I got my 93 and I cleaned it up a lot and felt better knowing all was good back there. get her "tuned up" and run her this summer. come on, summer..........

also, make sure you get a marine carb, not a standard auto one. again, ski dim is good.

learjet2230
01-04-2008, 07:54 AM
Hunter,
I have to disagree with part of your statement.

Yes that is correct, when you turn on the key the choke will close provided it is cold.

Irregardless of key position, if it is cold outside, the choke will be closed already. When you turn the key on you are putting a switched 12v input to the choke housing to heat it up and open it. It will take a minute or two depending on ambient temp. It is also designed to open as throttle is increased even when cold due to airflow over-riding spring pressure. This is why the shaft of the choke is not directly in the center of the butterfly. Once the engine is warm and the ambient heat under the engine box (heat rises) is sufficient to keep the choke housing heated, the choke should never close. Example, if you change skiers and shut the engine off, choke should stay open, even when the key is turned back on. There is no step plate on this carb as stated, and the accel pump statement is spot on. This is why we "pump" the throttle before start. We have to enrichen and "prime" the engine to compensate for the denser air when cold and reduced fuel atomization. The prime comes from our throttle action using the accel pump. Enrichment comes from the choke. Here is the idea of the accel pump, it does exactly what its name implies. When we pull up a skier and go from Idle, to high power, we "accelerate" the engine. If we just opened up the carb butterflies, we would allow all that air to rush in and lean out the engine (surge or cutout). We help it out with a 30cc shot of raw fuel to enrichen the mixture to help the carb "step up" from the idle jets to the main jets where we have enough vacuum to support the fuel metering needs.
I know maybe I am getting a little technical. This is what I do, teach mechanics about systems on Learjets. Except we dont use carburetors. We call them by there fancy names of Fuel Control Units and slap a fancy price tag on them. Except on a jet we control fuel, where on a carburetor we control air!