Pre Purchase advice - Maxum Boat Owners Club

Boatface · 08-23-2021, 09:32 PM

Hi there,

I am currently looking at a 1996 2000 SCL as my first boat to own and was hoping from some advice for the community :-)

I went out with the current owner today on the open sea for a tester, they are not true 'boaties', just bought it from the 'from new owner' last year when they moved to the coast and are now moving away.

While we were out there were some things that I noticed that I was hoping someone could shed some light on. Ultimately I am looking for red flags, things that I as a new owner should just walk away from. I am mechanically and electronically minded so am not scared of heavy maintenance but don't want to pay asking if I have work to do :-)

What I noticed is this:-

Cold start took a couple of tries to get going, but was then fine.

We pootled out of the harbour which was smooth (worked on cars before so know a poorly running engine when I hear one)

While out on the see I feel like we were doing allot of RPM for not much effort, at one point we were sat at 5k RPM and not what I assume is 'on the plane' just didn't feel that we were going very fast at all..

When we came back in to dock if you put the throttle / gear in neutral the engine would stall. Would start back up no issue, more forward, neutral, stall.

I had a good look at the engine and it seems relatively clean, is dry and free from corrosion.

My guess a the issue after some research is that it needs a new IAC valve for the stalling and starting thing and that assuming that it has the original prop, that the prob bush is shot causing the prop to slip at high RPM...

I am going to see the boat out of the water with the mechanic who maintains it in a few days time and was hopping that I could get some opinions on the above.

Naturally all advice will be taken as such and not gold plated letters of validation :-)

Thanks guys.

mmwjr · 08-24-2021, 01:26 AM

Well you didn’t tell us anything about how she’s powered; engine, drive carb,...

If a carb the starting issue may be a float issue. Stalling when shifting out of gear could be a bad lower shift cable if the drive is an Alpha. IAC is a MPI engine and opens when the engine is cold. Since it sounds like cold and warm idle isn’t an issue I doubt this is the fault even if it’s a MPI engine. What was the WOT rpm? Sounds like lots of little issues but need engine details to know.

Boatface · 08-24-2021, 01:08 PM

Quote:

Originally Posted by mmwjr

Well you didn’t tell us anything about how she’s powered; engine, drive carb,...

If a carb the starting issue may be a float issue. Stalling when shifting out of gear could be a bad lower shift cable if the drive is an Alpha. IAC is a MPI engine and opens when the engine is cold. Since it sounds like cold and warm idle isn’t an issue I doubt this is the fault even if it’s a MPI engine. What was the WOT rpm? Sounds like lots of little issues but need engine details to know.

Thanks for the reply, and apologies..

She is running a 4.3LXGen+ if that doesn't say it looks like carbs to me now I have looked and so that rules out the IAC as you say.

Drive is an Alpha One Gen2

Interestingly looks like it has a 5 blade prop on it which I believe is not stock...

As I said the current owners are not the types to be swapping props so if it was swapped it was done by the guy who owned it for 20 year from new....

Does not mean he could not me in the 'more always better' camp though :-)

gamoooos · 08-24-2021, 02:47 PM

It is a carb engine, and the carbs get gunked out sometimes…/ in terms of prop, yeah 5 will make you get on plane quickly but will be relatively slow; the stock is a 3 prop… swapping out the prop is cheap ($150), real easy and will make a huge difference

Boatface · 08-24-2021, 02:59 PM

Quote:

Originally Posted by gamoooos

It is a carb engine, and the carbs get gunked out sometimes…/ in terms of prop, yeah 5 will make you get on plane quickly but will be relatively slow; the stock is a 3 prop… swapping out the prop is cheap ($150), real easy and will make a huge difference

Thanks, I was thinking of going with a Revolution 4 14.6" 21 Pitch but that's based on research not experience or cost :-)

gamoooos · 08-24-2021, 03:32 PM

Depends what you plan on doing. 3 prop will get you more speed, 4 prop will get you on plane faster and will help if you do any type of towing (water ski, inflatables)

Boatface · 08-24-2021, 03:52 PM

Quote:

Originally Posted by gamoooos

Depends what you plan on doing. 3 prop will get you more speed, 4 prop will get you on plane faster and will help if you do any type of towing (water ski, inflatables)

For me personally Somewhere between the two, I want a well behaved and fun boat.. may do something with the kids towing wise but we are talking sub teens here.. not 100KG brutes :-)

But right now it's the odd performance I want to try and get an angle on before meet the owner this week to see the boat out of the water.

mmwjr · 08-24-2021, 04:36 PM

You may want to try Quicksilvers prop calculator to see what it recommends. Just Google for it and you find it.

jrsick · 08-24-2021, 05:10 PM

I think the tachometer is reading incorrectly. At 5k rpm, you should have noticed something significant. The tach has a 3 prong harness on the back that needs to be cleaned occasionally, along with the terminals on the back of the tach. Check that tach is set to 6.
Also possible that the prop has a spun hub.
Do you know what size prop you have?

Boatface · 08-24-2021, 06:06 PM

Quote:

Originally Posted by jrsick

I think the tachometer is reading incorrectly. At 5k rpm, you should have noticed something significant. The tach has a 3 prong harness on the back that needs to be cleaned occasionally, along with the terminals on the back of the tach. Check that tach is set to 6.
Also possible that the prop has a spun hub.
Do you know what size prop you have?

Thanks, When I am looking at the boat out of the water how to I check for that? Put her in gear and try and spin the prop ?

mmwjr · 08-24-2021, 10:28 PM

To check for a spun prop remove it from the boat and when looking at it from the part that faces away from the boat you will see a rubber ring that connects the inner and outer hubs. Use a center punch and mark two dimples that are inline with each other, one on the inner hub and one on the outer hub. Reinstall the prop and take the boat for a ride up to 4000 rpm. Come home and remove the prop and inspect to see it the two marks are still aligned, if not the hub is spinning. This can be repaired but you can probably get a new prop for just a little more money.

Boatface · 08-26-2021, 04:01 PM

So, I have been to see the boat today and it's got a 'High Five' 23" pitch I think
(48-815762 A45 23P) on it.

The prop was heavily coated in algae which has now been thoroughly cleaned etc. Will see on Tuesday if that makes any kind of difference. No signs of impact on the blades or anything.

I did notice that she does stall allot when shifted to neutral but again unless someone tells me otherwise I am going to assume that this is just the same as my first car and she just needs the Timing, Cleaning and tuning treatment...

As ever value opinions.

jrsick · 08-26-2021, 04:18 PM

With a 23p prop you would be going 70mph at 5k rpm. Tach is off or spun hub.
For stalling, what is the idle rpm?

Boatface · 08-26-2021, 04:38 PM

Quote:

Originally Posted by jrsick

With a 23p prop you would be going 70mph at 5k rpm. Tach is off or spun hub.
For stalling, what is the idle rpm?

So, is it possible to spin a hub without hitting something? E.g. just from raw torque. The prop selector seems to only ever give me 21P so is it case of the high pitch and heavy hand on the throttle could spin the hub?

The mechanic who was with us today (looked after the boat since new) seemed to be of the view that as the core of the hub was still in there it was ok... that the plastic shell that makes up the hub just blows to bits...

But again, if it's just been torqued out like over tightening a screw then why would it just 'blow to bits'

mmwjr · 08-26-2021, 07:28 PM

Stalling when shifting out of gear is most likely a worn lower shift cable which is keeping the shift interrupt switch closed too long.

Boatface · 09-02-2021, 07:53 PM

Well, I took the plunge and all seems well, I have tweaked the idle speed up a smidge and it's not stalled since.

Still not convinced on the rpm and stuff but when I take her out of the water for the winter I am going to replace the hub just for the experience and see how we go from there.

Couple of questions if people have any ideas:-

At idle when inspecting the engine I can hear what sounds like an electrical spark jump, really fast and constant, seems to be coming from the coil area but not 100% sure on that. I would say it's a perished HT lead with some arcing going on but last time I experienced that in a car the engine would hardly run.

Also there is a constant squeaking coming from one of the pullies at the front, my car brain is looking at the Alternator (replaced at least once in the boats life so about a decade old) or the water pump, would value others opinions.

https://youtu.be/2--WoeGkTYo

Lastly, does anyone have a good source of things like windscreen seals, cuddy door lock handle etc for these Maxum boats ?

Thanks guys.

mmwjr · 09-02-2021, 10:51 PM

Running the engine at dusk will allow you to see ignition spark jumping if it’s happening. Try removing the belt and run the engine to verify the noise goes away then hand turn each pulley to feel for roughness and sound. To me it sounds like the idler pulley.