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View Full Version : 87 Prostar, Rebuilt 351, NO TOP END...


aikijodo
05-29-2007, 10:06 AM
Hello,

I am hoping that the brillant, experienced minds on this site can provide a few suggestions. Here's what I know...

Bought the boat last year, used it for 25 hrs, 625hrs on boat, 25 hrs on new engine (have receipts, engine installed in 2002). Starts, idles and has a max speed of 28mph(via GPS) @ 2200 RPMs which is the maximum I can get the engine to achieve during load.... Obviously something is wrong....

1) New Holley Carb (4160, I think, how do you identify?)
2) Max RPMs under load are 2200rpm can rev higher in neutral
3) Secondaries are not opening, tried various diaphragm springs (Yellow-Light current installed).... (assume RPMs are not increasing because of this... correct?)

Other than this performance problem, the boat is reliable and consistent.

Any thoughts/suggestions are greatly appreciated as we'd love this boat to actually perform.

Hunterb
05-29-2007, 12:41 PM
Have you checked the obvious things like the throttle cable and ensuring that the timing is set correctly? Have you tried disconnecting the cable and opening the throttle by hand? The secondaries will not open at the RPM's you are reaching......... or I don't believe they will anyway. If it's a 4160 you may want to pull both bowls off and make sure the floats are set correctly and that the needle valves are working properly. If you have been changing the vacuum springs make sure the little check ball that's in there didn't fall out. A faulty or non-functioning distributor advance mechanism might cause the symptoms you are seeing. Do you have points or electronic ignition?
Who did the rebuild? Is there a possibility that they screwed something up? Has it run properly at any time since the rebuild?

Start with the easy stuff first and see how it works. Post back with more info and I'm sure someone will be able to help you out. Good luck !! If you're a skier you will love the boat when you get it running right.

Here's a decent article on refurbising a 4160 carb

http://www.fordmuscle.com/archives/1999/12/holley/index.php
Bruce

Ryan
05-29-2007, 01:12 PM
Any thoughts/suggestions are greatly appreciated as we'd love this boat to actually perform.


Stick to wakeboarding. :D

Hunter gave every answer I could think of.

TRBenj
05-29-2007, 01:19 PM
A faulty or non-functioning distributor advance mechanism might cause the symptoms you are seeing.

Bingo. Check initial timing (should be about 8-10 degrees) and see if it advances with RPM. You can do this at idle (no load). You should see full advance (initial + ~20 degrees) by 3000 RPM. Im betting you have a broken spring.

aikijodo
05-29-2007, 02:01 PM
Thank you, I greatly appreciate the thoughts and suggestions. Unfortunately, I committed the sin of all sins and bought the boat several hours from home after talking to the previous owner, starting the engine on land (sounds good ;-) and reviewing the rebuild documentation. I did not test drive it (brilliant!), nor did the previous owner because he had a medical issue after the rebuild and stored the boat for 4 years, until he found a sucker (me) to buy it. But, I did negoitate a "good" price, well maybe I did (if I can get it to perform) ...... It does look good with new paint, new interior, wake board tower, etc.... All show and little go....

So, I am starting from scratch and cannot find a mechanic on my lake (Lake Wallenpaupack, Pa) who will work on a 20 year old engine. The people who did the rebuild are A) too far away and B) won't touch it because it has been several years and a change of owner.

I don't know enough about engines to determine if this is a simple issue with the carb or something more sinister. I'll investigate the suggestions. A few I simply don't know (yet), such points or electronic ignition (it has an inginition coil is that electronic?). I believe that the throttle is opening full but will try it by hand. I'll find someone to check the timing.

I really appreciate the help, because I am determined to get this boat operating correctly. Last year was fun, wake boarding and tubing can be sufficiently experienced without the extra power, but everything would be awesome with proper power.

Hunterb
05-29-2007, 02:35 PM
Hmmmm. It's very hard to say what's going on. Hopefully it's something simple. If you are not very familiar with engines then it might pay to take it to someone to do a tune-up and check the timing advance etc. so you can eliminate those possibilities. I'd also suggest a compression test and a vacuum test which would give you a good idea of how the engine 'internal organs' are working. If all that checks out then the problem would most likely be carb related. Normally if the distributor advance spring is broken you won't get very good performance, especially when you try to give it lots of throttle, and I'd be surprised if it ran well enough to wakeboard behind. When you say it won't go beyond 2200RPM what does it do if you keep pushing on the throttle? Is is smooth or does it bog down? Does it smoke a lot?

You may save yourself a lot of grief if you take it to someone and tell them what it's doing. Any mechanic should be able to work on that motor, they don't come any simpler.

Good luck. They are a lot more fun when they run right.

Bruce

etduc
05-29-2007, 03:02 PM
What Hunterb said. :)


Hello,

I am hoping that the brillant, experienced minds on this site can provide a few suggestions. Here's what I know...

Bought the boat last year, used it for 25 hrs, 625hrs on boat, 25 hrs on new engine (have receipts, engine installed in 2002). Starts, idles and has a max speed of 28mph(via GPS) @ 2200 RPMs which is the maximum I can get the engine to achieve during load.... Obviously something is wrong....

1) New Holley Carb (4160, I think, how do you identify?)
2) Max RPMs under load are 2200rpm can rev higher in neutral
3) Secondaries are not opening, tried various diaphragm springs (Yellow-Light current installed).... (assume RPMs are not increasing because of this... correct?)

Other than this performance problem, the boat is reliable and consistent.

Any thoughts/suggestions are greatly appreciated as we'd love this boat to actually perform.

A new out of the box Holley, should run pretty good.(At least better, than what your saying.) Fine tuning/adjustments only, unless you live at extreme elevations. (I'm talking basic tuning, here.)

How high will it rev, in neutral? 3000, 4000, 4500,etc. How smooth, does it rev? If it won't go much over 3000, probably not the carb. Could be a number of things, even non engine related.

Don't assume anything. Do a simple tune-up, put everything back to base settings. Confirm your distributor advance is functioning. (How old is your distributor?)

aikijodo
05-29-2007, 03:06 PM
To address the recent questions..

2200 rpm is at WOT and the secondaries are not getting fuel, but the ride is smooth with no smoke.


One more piece of interesting/wierd data....

The previous owner had the bottom of the boat refinished in Rhino Lining instead of paint or gelcoat. This added some weight about 200lbs and additional surface area. No doubt the boat will be slowed... and...
Obviously not a good thing, but would it prevent the engine RPMs and Secondaries from operating correctly?

Ryan
05-29-2007, 03:23 PM
The previous owner had the bottom of the boat refinished in Rhino Lining instead of paint or gelcoat. This added some weight about 200lbs and additional surface area. No doubt the boat will be slowed... and...


eeek gad!!! Can you post some pics of the hull?

etduc
05-29-2007, 03:23 PM
....I don't know enough about engines to determine if this is a simple issue with the carb or something more sinister. I'll investigate the suggestions. A few I simply don't know (yet), such points or electronic ignition (it has an inginition coil is that electronic?). I believe that the throttle is opening full but will try it by hand. I'll find someone to check the timing. ......


Oooh, there's your problem. Didn't read this post. Hunterb is, again, right on the money. A 351w(Ford) is very basic, easy tune-up. My father-n-law, has his jetboat tuned at the local insta-tune. Be sure to take fake-a-lake, and hook it up for them, or your impellar will be fried!

If you have a point style distributor, buy an electronic distributor and coil. (Life will just be better. Grass greener, sky bluer.) Don't convert an old distributor. Buy a new distributor and a new coil.

Hunterb
05-29-2007, 03:26 PM
Oh my, Rhino lining on the hull. This gets more interesting all the time. That will not affect your engine RPM's. I will not comment on how it might affect the overall performance of the boat other than to say it's probably not positive.

Get a mechanic to do a good tune-up on it and make sure to tell him what the current symptoms are. I suspect that will fix your problem. At the very least, it should identify your problem and you can then decide what route to take to fix it.

Good luck !!

Bruce

etduc
05-29-2007, 03:35 PM
To address the recent questions..

2200 rpm is at WOT and the secondaries are not getting fuel, but the ride is smooth with no smoke.


One more piece of interesting/wierd data....

The previous owner had the bottom of the boat refinished in Rhino Lining instead of paint or gelcoat. This added some weight about 200lbs and additional surface area. No doubt the boat will be slowed... and...
Obviously not a good thing, but would it prevent the engine RPMs and Secondaries from operating correctly?

Rhino Lining! Guess you don't even, bother loading on a trailor, you just drag it home. ;)

2200 rpm wot, in neutral! If your carb throttle plates, are open. The primary should take you beyond 2200 rpm.

It is not your carb.

aikijodo
05-29-2007, 04:00 PM
eeek gad!!! Can you post some pics of the hull?

http://www.tmcowners.com/photopost/showphoto.php?photo=4148&cat=501

Not a terrific pic. but for the group's entertainment, I'll provide close-ups of the hull next week.

aikijodo
05-29-2007, 04:04 PM
Rhino Lining! Guess you don't even, bother loading on a trailor, you just drag it home. ;)

2200 rpm wot, in neutral! If your carb throttle plates, are open. The primary should take you beyond 2200 rpm.

It is not your carb.


... will go to at least 5000rpm in idle.... Can only obtain 2200rpm under load.

Ryan
05-29-2007, 04:17 PM
Could it could be something as simple as the wrong prop? I mean seriously wrong...
Maybe not, even a 14x17 would get the RPMs up even if the boat didn't accelerate much. Just thinking outloud.

Storm861triple
05-29-2007, 05:09 PM
There have been a lot of good ideas here but the OP said that the secondaries aren't opening. IF THIS IS TRUE, then the throttle linkage is the first thing to check. The secondaries should open at least a little regardless of the prop, hull coating, timing, etc.

Does this carb have a choke/high idle linkage? If so, and the choke isn't opening all the way, that would prevent the secondary throttle from opening. Although the engine should make it to at least ~2800 RPM on just the primaries alone.

OP: Try removing the throttle cable from the carb, and while someone is driving the boat, you actuate the throttle AT THE CARB, and see if your results are better. Post back here. Impliment all safety prctices for this exercise.

-Tom

viabill
05-29-2007, 05:34 PM
Storm is correct... if the secondaries are not opening, that is key to diagnosis.
Incorrect prop, hull drag, etc. are not the issue at this point.

Secondaries not opening will be caused by, as mentioned, throttle cable not pulling to WOT, low fuel supply, incorrect timing, or a problem in the carb (wrong jets, inop needle & seat, missing check ball, obstruction in the secondary fuel feed tube, blocked venturi vacuum orifice supplying the secondary diaphragm, sticking or incorrectly assembled diaphragm assembly). That's about all that can cause the secondaries to remain closed.

If the hull drag were slowing it down, it would do it as the carburetor is howling with all four barrels trying to get the boat up to speed. Same for incorrect prop.

Hunterb
05-29-2007, 05:50 PM
Something I hadn't thought of before was restricted fuel flow or a fuel pump that's lost its enthusiasm. Have you checked your fuel filter(s) and screens? There should be an in-line filter, one in the bowl of the fuel pump and a screen where the fuel line goes into the carb. There may also be a screen where the fuel line exits the tank. A restriction at any of those places may cause your symptoms. I don't know the procedure for testing your fuel pump but I'm sure there is some way to do it. If it will rev up with no load, as stated, but not under load then I suspect a fuel supply problem.

Good luck again. I suspect you have a simple problem.

Bruce

aikijodo
05-29-2007, 06:46 PM
Some Fuel issues were uncovered by a Mastercraft dealer last year. New filters were supplied, but the pump wasn't checked. The dealer wasn't overly interested in exploring further because of the boats age and their "workload'. After all of the assistance this forum has provided today, I called the MC dealer and have arranged for them to take another look at the issue. Hopefully one of their mechanics cares enough and is skilled enough to resolve the problem.

The suggestions y'all have provide will at least enable me to query them and keeping working toward a solution.

I'll not be able to get the boat to them util next weekend, but I am feeling better that this might feasibily be resolved.

Very much appreciated... This is an awesome group....

wesgardner
05-31-2007, 10:09 AM
My shifter/throttle was all boloxed up when I bought my boat and exhibited some of the same issues....I'd try the "operate the throttle manually at the carb" idea....

BrianM
05-31-2007, 10:32 AM
The dealer wasn't overly interested in exploring further because of the boats age and their "workload'. .
Do you happen to have another dealer within a reasonable distance? This one sounds like they are less than desirable. Your money spends the same as anyone elses. If you scheduled an appointment and pay your bill they should be willing to track down a problem for you. :twocents:

aikijodo
07-06-2007, 10:51 AM
Problem Resolved.... While I don't have a complete grasp of the situation the following is what I think I heard from the mechanic.

Apparently, whoever installed the upgrade to an electronic ignition system, reversed 3 of the 8 magnets, thereby effectively causing 3 of the cyclinders to not fire....

I appreciate the help from this forum.

mayo93prostar
07-06-2007, 11:31 AM
Glad to hear it works. It looks like a very nice boat from the one pic. post more pics, especially of the hull with coating. from the pic, it does not look like liner coating but hard to tell. plus if you can clarify what the problem was it would be nice for all of us, especially those that offered ideas as to what the real problem was. i find it hard to believe you could pull a wakeboarder with only 3 cylinders working but it sounds like the timing was all messed up if the magnets were not right. have a good summer! another thing to check still if the secondaries work. I found mine rusted shut and had to free up with penetrating oil and then polish up some to move freely. they are vacuum operated on some carbs.