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View Full Version : Do I need to rebuild my '89 ProStar's carb?


tdjaster
10-05-2011, 10:07 PM
I need some tech help.

We have an '89 ProStar with about 650 hours on it. We bought it in April, it runs great, but we've definitely put more use on it this year than it's seen in a long time. I just took it to the dealership because it had a water leak somewhere in the engine and because it would cough/sputter/sometimes shut off when pulling a skier up out of the water. It was mostly good when it got on plane and cruised at 20mph+.

The dealership put on a new water pump, fuel pump, points, and just cleaned things up, which it needed...but the sputter/cough problem wasn't cured. So I just put $600+ into it but my boat is still sick.

I spoke with the service guys on the phone and they said it might need a complete carb rebuild but they wouldn't know without testing it for sure (the reason they didn't do this in the first place was to save me some money and because they thought their first steps would do the trick...which I approved of, so I'm not mad at them).

I'm handy and can fix lots of things but I lack the ability to diagnose what is wrong. I also want to try the do-it-yourself method for cost saving and knowledge gaining reasons. Therefore:

#1. Does this sound to you like it's a carb issue?
#2. Is that something that an "amateur" mechanic can solve easily/affordably?
#3. Am I better off just taking it back to the shop?
#4. Could it be something completely different?

I appreciate anyone who can give me a hand on this one and share some knowledge.

I eagerly await your responses.

Thanks ya'll!

Troy

mcboi52
10-05-2011, 10:30 PM
Do you use fuel treatment? The reason I ask is because I was having similar issues at one time with my 89' Prostar and was told to use treatment to help with condensation is the gas tank. It took about a full tank to run through before it went away.

MCfreak227
10-05-2011, 10:31 PM
First of all i know its a dumb question but why was the fuel pump replaced? those mechanical fuel pumps usually have no problems as long as its pushing 6-8psi to the carb its fine. I do not mean to insult you or the shop with such a remedial question but i have to ask...is there good fresh gas in the boat? Not fresh gas mixed with old gas but fresh fuel only in the boat?

If so..It's truly hard to say with confidence that it sounds like a carb problem words can only do so much justice. Did the shop you took the boat to do a compression test on your engine? And believe it or not I have seen alot of "technicians" put points in a boat and not re check ignition timing which could also cause a lack of holeshot power.Im not sure exactly what kind of carburator youre running but chances are its probably a Holley which can be a tricky one to rebuild for a first timer if you have never been into a carb before. And rebuild kits are not cheap. I HIGHLY RECOMMEND YOU USE A HOLLEY REBUILD KIT!! or whatever brand carb you have get the manufacturer produced rebuild kit the aftermarket kits are worthless!

I would deffinetly check out the following before doing the carb:
-condition of your fuel....if its really bad gas might as well order your carburator kit and rebuild it
-Spark plugs and wires were they changed when the points and tune up were done?
-check engine compression if the shop did not perform this test
-Ignition timing (is it set to the correct factory specification?)

j.mccreight@hotmail.com
10-05-2011, 10:41 PM
Holley carburetors are not hard to rebuild as long as you pay attention to what you take apart. Google and you-tube can help with step by step instructions as well as holley website. Holley 4160 marine kits are cheap like 40 bucks. I doubt its bad gas since it sounds like you've gone through many hours of use. Does it act up more when cold or all the time even warmed up? You might just have to adjust your choke.

http://www.summitracing.com/parts/HLY-703-47/

Skipper
10-05-2011, 11:08 PM
Don't waste your time and money on a carb rebuild. I had an '89. I had the carb rebuilt twice and did it myself once. Sure, anybody with some skills can do it. Yes it works well for a minute. But I finally got fed up with rebuilding the stupid 20 year old carb and bought a new one. Holy smokes Batman!!! The freaking boat ran like a champ. I started spending my days enjoying the boat. It started, it idled, it ran really fast, I could turn it off and turn it back on. It could be hot, cold, daylight or dark. The stupid thing worked great. It was like having a brand new boat except it was 20 years old. But the moral of the story is buy a new carb.

1redTA
10-05-2011, 11:23 PM
ditch the points

tdjaster
10-07-2011, 09:13 AM
Thanks for all of the help. Please see my responses below and offer any further help you can.

tdjaster
10-07-2011, 09:14 AM
Do you use fuel treatment? The reason I ask is because I was having similar issues at one time with my 89' Prostar and was told to use treatment to help with condensation is the gas tank. It took about a full tank to run through before it went away.


I did one bottle of fuel treatment one time. It had about a half tank of gas when I picked it up from the shop and went to the lake. We ran just about all of it out and then filled it up on the way home. That was Saturday, I haven't taken it out since then.

tdjaster
10-07-2011, 09:16 AM
First of all i know its a dumb question but why was the fuel pump replaced? those mechanical fuel pumps usually have no problems as long as its pushing 6-8psi to the carb its fine. I do not mean to insult you or the shop with such a remedial question but i have to ask...is there good fresh gas in the boat? Not fresh gas mixed with old gas but fresh fuel only in the boat?

If so..It's truly hard to say with confidence that it sounds like a carb problem words can only do so much justice. Did the shop you took the boat to do a compression test on your engine? And believe it or not I have seen alot of "technicians" put points in a boat and not re check ignition timing which could also cause a lack of holeshot power.Im not sure exactly what kind of carburator youre running but chances are its probably a Holley which can be a tricky one to rebuild for a first timer if you have never been into a carb before. And rebuild kits are not cheap. I HIGHLY RECOMMEND YOU USE A HOLLEY REBUILD KIT!! or whatever brand carb you have get the manufacturer produced rebuild kit the aftermarket kits are worthless!

I would deffinetly check out the following before doing the carb:
-condition of your fuel....if its really bad gas might as well order your carburator kit and rebuild it
-Spark plugs and wires were they changed when the points and tune up were done?
-check engine compression if the shop did not perform this test
-Ignition timing (is it set to the correct factory specification?)


Fuel pump was replaced. There is fresh gas in there now but haven't run it off of this tank yet.

I don't remember if they did a compression test or not. I know spark plugs and wires are good.

tdjaster
10-07-2011, 09:16 AM
Holley carburetors are not hard to rebuild as long as you pay attention to what you take apart. Google and you-tube can help with step by step instructions as well as holley website. Holley 4160 marine kits are cheap like 40 bucks. I doubt its bad gas since it sounds like you've gone through many hours of use. Does it act up more when cold or all the time even warmed up? You might just have to adjust your choke.

http://www.summitracing.com/parts/HLY-703-47/


How do I adjust the choke?

tdjaster
10-07-2011, 09:17 AM
Don't waste your time and money on a carb rebuild. I had an '89. I had the carb rebuilt twice and did it myself once. Sure, anybody with some skills can do it. Yes it works well for a minute. But I finally got fed up with rebuilding the stupid 20 year old carb and bought a new one. Holy smokes Batman!!! The freaking boat ran like a champ. I started spending my days enjoying the boat. It started, it idled, it ran really fast, I could turn it off and turn it back on. It could be hot, cold, daylight or dark. The stupid thing worked great. It was like having a brand new boat except it was 20 years old. But the moral of the story is buy a new carb.


When you say that you bought a new carb, does that also mean that you did it yourself or did you have it done professionally?

thatsmrmastercraft
10-07-2011, 11:16 AM
How do I adjust the choke?

On a cold engine, you want to have the choke closing almost all the way when you pump the throttle once to set the choke and fast idle speed. Then once it starts, the choke should open fully in short order (30 seconds to a minute). You can adjust this by loosening the three screws on the choke spring housing and rotating the choke spring assembly. Remember to tighten the 3 screws when you are done. If the choke won't open quickly enough to keep the engine from choking out, you may need to replace the choke assembly (make sure you have power going to it when it starts). The choke is just a bi-metallic spring (two different rate springs bonded together) and do wear out over time. They aren't overly expensive and easy to replace.

tdjaster
12-15-2011, 10:51 AM
Just wanted to give an update...

I changed the spark plugs, distributor cap, and rotor and the motor runs beautifully. All together it was probably $50 in parts and a hour or two in time that I put in.

Thanks everyone for the help!

madcityskier
12-15-2011, 11:56 AM
Glad to hear it.
I'm still stuck on the water leak in the engine. Do you mean water getting into the hull (manifolds for instance) or water where it shouldn't be within the engine (in the oil for instance)?

tph
12-15-2011, 12:38 PM
Don't waste your time and money on a carb rebuild. I had an '89. I had the carb rebuilt twice and did it myself once. Sure, anybody with some skills can do it. Yes it works well for a minute. But I finally got fed up with rebuilding the stupid 20 year old carb and bought a new one. Holy smokes Batman!!! The freaking boat ran like a champ. I started spending my days enjoying the boat. It started, it idled, it ran really fast, I could turn it off and turn it back on. It could be hot, cold, daylight or dark. The stupid thing worked great. It was like having a brand new boat except it was 20 years old. But the moral of the story is buy a new carb.

I had a similar experience. The new carb was not cheap but it was worth it.

Cloaked
12-15-2011, 05:24 PM
One of the best moves you can make with the older (aged) 4160s. I have rebuilt many 4160s in this application and sooner or later they get to the point of being less and less efficient and cooperative. Replacement is around $500 but it will give new life to the engine for another 10 - 15 years. Here lies the importance of stabalizing the fuel when it sets in the carb for long periods of time. I have resorted to treating fuel every tank and have had much cleaner running carbs for the last few years.

.

oldairboater
12-19-2011, 11:49 AM
People sometimes forget that worn butterfly shafts make tuning an old carb impossible. That I think is why a new carb always makes such a big difference sometimes.

1redTA
12-19-2011, 12:29 PM
People sometimes forget that worn butterfly shafts make tuning an old carb impossible. That I think is why a new carb always makes such a big difference sometimes.

that is valid point! the surface area of the butterfly multiplied by the vacuum of the engine will tell you the amount of force pulling against the shaft they ride on

03geetee
12-19-2011, 04:23 PM
Previous owner replaced the carb on my 83 with around 2100 hrs on the orginal. I dont know how the boat ran before, but these statements about just buying a new carb couldnt be more TRUE. The boat runs, idles and starts like a dream. No hesistation or stumbling no matter what the weather, start her up after a cool nights nap and she idles high for a minute then blip the throttle and she settles down everytime. Almost seems like it has EFI.

Like one poster said it makes a 29 year old boat feel like new.

JTR