Jump to content

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

Sign in to follow this  
DrFred

Hammerhead Problem

Recommended Posts

DrFred

I have a 2002 wakesetter xti with a hammerhead motor. It runs fine all the time except during wide open throttle from Idle. It runs fine at wide open throttle if I get there gradually. When starting from idle and punching to WOT, it virtually always hesitates midway through acceleration and often several times. It sometimes backfires (that'll scare you). I'd like to avoid changing every part in the fuel delivery system or electrical system. Does anyone recognize this problem and know the solution? This way i can take it to a local marina with a plan.

The only modification to the motor is the addition of perfect pass (by the malibu dealer, 2+ hours away). The only part i have possibly personally damaged is the Knock sensor on the starboard engine block (this needs to be removed with a wrench to winterize the motor) it looks ok though.

If it needs a computer evaluation, is it true that for this model year, the Mercruiser computer works?

Thanks in advance

Share this post


Link to post
skicrave

First thing you need to do right away is replace your fuel filters.

If that doesn't solve the problem, then hook up a pressure gauge to the fuel rail to see what kind of readings you're getting on key up.

Report back.

Share this post


Link to post
BillFooter

My Response has the Hammerhead 365. If I have idled for a bit and then throttle hard mine will have a slight hesitation, then backfire. It only backfires once, then takes off. It does it worse when the engine temp is cool. If you ease into the throttle it does not do this. I had the dealer check it a couple of years ago, but as usually is the case they can't find any problems. My fuel filter condition does not alter the problem.

My Hammerhead is also one that 'makes' oil. It runs rich enough that it gets a lot of fuel in the oil. I talked to a tech at Indmar about sending them my computer to re-flash, but he said that would not remedy the problem. He suggested that I change the the thermostat to a 180 degree. It might help both problems.

Edited by BillFooter

Share this post


Link to post
electricjohn

Hesitation on take off is a sign of retarded timing or a lethargic MAP sensor.

DrFred I would replace your fuel filters first though.

Share this post


Link to post
25lsvwakesetter

+1 on the Fuel Filter.

Messed up fuel delivery = messed up fuel/air mixture by computer = big bang(sometimes).

Edited by 25lsvwakesetter

Share this post


Link to post
wienrdog

Plus1.gif on the fuel filter. Been there, done that, got the T-Shirt. Exact same symptoms, minus the backfire.

BTW - Welcome.gif to 'The Crew'.

Share this post


Link to post
DrFred
Hesitation on take off is a sign of retarded timing or a lethargic MAP sensor.

DrFred I would replace your fuel filters first though.

Thanks-

I will replace the fuel filter first, but rumors abound that this doesn't seem to solve the problem. The fuel filter is supposed to be in-line, probably under a floor board. I'll take a look for it and see if I can find it and whether or not its a job i can attempt. Thanks for your help.

Share this post


Link to post
25lsvwakesetter
Hesitation on take off is a sign of retarded timing or a lethargic MAP sensor.

DrFred I would replace your fuel filters first though.

Thanks-

I will replace the fuel filter first, but rumors abound that this doesn't seem to solve the problem. The fuel filter is supposed to be in-line, probably under a floor board. I'll take a look for it and see if I can find it and whether or not its a job i can attempt. Thanks for your help.

My fuel filter 05 8.1 is inline starbord side mounted approx 12 inches away from the transmission. Changes out in 2 minutes. Looks like attached image..

Good luck!

post-572-1211044890_thumb.jpg

Share this post


Link to post
DrFred

Ok-

Spent the last couple hours upside down trying to find the fuel filter. There is nothing on the block. I removed the rear seat and had a cleaning diversion. A fuel filter wasn't seen between the block and under floorboards looking on port side along prop shaft. I did find a very loosely fitting electrical sensor connector just above oil filter. I'll post a pic of it as soon as i figure out how.

So- Where is the fuel filter? 2002 Malibu wakesetter xti.

Share this post


Link to post
electricjohn

Probably on top of the fuel tank in the first 6 inches of fuel line. That's where mine was, but I relocated it to under the removable floorboard, because getting to my fuel tank was a major task. The item you found near the oil filter is either the oil pressure sender (larger) or the oil pressure switch (smaller). The sender is for your gauge and the switch goes to the computer which will sound an alarm if your oil pressure drops below 4-6 psi.

Share this post


Link to post
DrFred
Probably on top of the fuel tank in the first 6 inches of fuel line. That's where mine was, but I relocated it to under the removable floorboard, because getting to my fuel tank was a major task. The item you found near the oil filter is either the oil pressure sender (larger) or the oil pressure switch (smaller). The sender is for your gauge and the switch goes to the computer which will sound an alarm if your oil pressure drops below 4-6 psi.

Thats gotta be right. The fuel filter has to be either in or just outside the tank. Id have to remove the rear seat and the support for the rear seat. I don't have to remove or pull up on the tank, do I?

Share this post


Link to post
DrFred

I just removed the rear seat and supports. The fuel filter is still not visible. If I remove the floor board (which looks like having to take apart the support of the front stadium seat) will that give me access to the fuel filter, or will I have to drain and unbolt the fuel tank? What were they thinking? And BTW, assembly workmanship is sloppy. (Phillips head screws, off center and needing a very long #2 screwdriver to reach.)

Share this post


Link to post
electricjohn

Fred, That is why I relocated my filter. And yes I have to agree with you on the craftmanship. I don't know how the XTI is layed out, but I had to remove the backpanel of my carpeted ski locker (trunk) to access the filter. The 14 screwheads were all sunk into the carpeting which required a stud finder for locating them and about half of them were so overtightened that they were striped out which made removal nearly impossible. I ended up using oversized screws and grommets when replacing them so the screws are visible now if I ever have to remove that backpanel again to replace any other part such as the bilge blower.

No, I doubt you will have to remove the fuel cell.

The funny part about the whole task was that my 4 year old filter with 200+ hours was as easy to blow through as the new one.

Share this post


Link to post
DrFred
Fred, That is why I relocated my filter. And yes I have to agree with you on the craftmanship. I don't know how the XTI is layed out, but I had to remove the backpanel of my carpeted ski locker (trunk) to access the filter. The 14 screwheads were all sunk into the carpeting which required a stud finder for locating them and about half of them were so overtightened that they were striped out which made removal nearly impossible. I ended up using oversized screws and grommets when replacing them so the screws are visible now if I ever have to remove that backpanel again to replace any other part such as the bilge blower.

No, I doubt you will have to remove the fuel cell.

The funny part about the whole task was that my 4 year old filter with 200+ hours was as easy to blow through as the new one.

JOhn-

I removed the floor board (and both seats and supports) and determined that the filter, if accessible, would have to be through the rear ski locker and all the screws are sunk into the carpet. I didn't realize some of the screws sunk into the carpet were #3 phillips and had bolts on the backs (and I stripped one of these) My ski locker has a shower in it, so add a few more screws and bolts. So, my buddies think its the MAP sensor. Should I leave the filter alone? Is a MAP sensor replaceable without splicing, soldering or pulling the motor out?

My bilge blowers are right in the engine compartment....

Fred

Share this post


Link to post
electricjohn

Not sure where the MAP is located on the Hammerhead, but mine is on/in the rear of the manafold/flame arrester. It is a plug and play item. It will have a grey, green, and black wire going to it.

Edited by electricjohn

Share this post


Link to post
DrFred

I replaced the Fuel Filter today. It was an exact NAPA 3299 fuel filter. It seems to have solved the problem (so far). <The problem was hesitation when warm under WOT>. After spending 6hrs finding it, I replaced it in 5 minutes (in the Malibu 2002 Xti (one XTi model that year) it was behind the ski locker. Phillips head screws in carpeted ski locker had to be removed (most were stripped) . Thanks to all that contributed. I will make another post if the problem returns.

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...