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!

Engine running rough, help needed


Recommended Posts

I recently bought a 2004 Response LXi with the Hammerhead 380 engine with 300 hours. It came from a bankruptcy sale and the seller didn't have the maintenance records. I took a chance on it because the price was right. It was running rough when I got it so I decided to do all the tune-up work on it that I could.

I started by changing the plugs, and it ran much better after that. When I pulled the old ones out, one of them broke when I pulled the plug wire off and a second one wasn't even tight. I was able to remove it without even using the wrench.

I also ordered a bunch of new parts for it, and when they came in installed them as well, including new distributor cap and rotor, impeller, fuel filter, drive shaft packing and new oil and filter. After doing all of that, it ran rough again, like it did before I changed the plugs! All of the parts came from Discount Inboard Marine, so I feel pretty confident that they were the right parts and of high quality.

What could I have done that would make it run rough again? I was very careful when installing the new distributor cap to put the plug wires back on in the correct location, even looking up the firing sequence and verifying that it matched the way the plug wires are attached.

Any help would be appreciated.

Thanks,

Jeff

Edited by jcochrane007
Link to comment

After I changed the spark plugs, when it was running good, I ran it down to about a quarter tank before refueling, so it should have pretty fresh fuel. I did change the fuel filter with this last batch of repairs. I'm assuming that the arrow on the fuel filter indicates the direction of flow? I installed the filter so that it points from the gas tank towards the engine.

I just don't understand why it would run worse after replacing all that stuff. It was really running MUCH better before.

Link to comment

Distributor cap on nice and tight and seated properly?

I'd be tempted to replace the fuel filter again, cut the old one in half and see what it looks like.

-Chris

Link to comment

When you changed the plugs it ran fine. With that in mind and the fact you commented that you changed plug wires and the fact that 2 plugs were broken or bad, my vote would be to go back through the spark system since you feel that it runs like it did before you changed plugs. I would recheck the firing order, and ensure all the plug wires are tight. I would go back over all the steps I did to see what I might have done to cause the problem. After that, then I would chase other potential problems like fuel delivery.

Link to comment

To clarify, I didn't install new plug wires. I just replaced the distributor cap and rotor. I'm tempted to put the old cap and rotor back on and see what happens.

Link to comment

When you changed the plugs it ran fine. With that in mind and the fact you commented that you changed plug wires and the fact that 2 plugs were broken or bad, my vote would be to go back through the spark system since you feel that it runs like it did before you changed plugs. I would recheck the firing order, and ensure all the plug wires are tight. I would go back over all the steps I did to see what I might have done to cause the problem. After that, then I would chase other potential problems like fuel delivery.

Plus1.gifexactly what i was thinking

edit to add: guess i should have read the post that followed.

i'd throw a set of wires on it then take woodski's advice.

Edited by tvano
Link to comment

try the old cap and rotor if they look ok.

The first thing you did was change the plugs right? and it ran good/better than when you got it. Then you replaced other stuff and ran as bad as when you got it.

Do you new boat guys have points under the distributor cap?

Did you clean the screen at the bottom of the fuel pump. If you have one.

Link to comment

Your cap and rotor can only go on one way. Be careful changing your wires make sure you get the firing order correct. RE Set your timing. Sounds like you have done everything but wires and timing. Make sure that is done and that will eliminate the ignition system.

Link to comment
  • 3 weeks later...

I recently bought a 2004 Response LXi with the Hammerhead 380 engine with 300 hours. It came from a bankruptcy sale and the seller didn't have the maintenance records. I took a chance on it because the price was right. It was running rough when I got it so I decided to do all the tune-up work on it that I could.

I started by changing the plugs, and it ran much better after that. When I pulled the old ones out, one of them broke when I pulled the plug wire off and a second one wasn't even tight. I was able to remove it without even using the wrench.

I also ordered a bunch of new parts for it, and when they came in installed them as well, including new distributor cap and rotor, impeller, fuel filter, drive shaft packing and new oil and filter. After doing all of that, it ran rough again, like it did before I changed the plugs! All of the parts came from Discount Inboard Marine, so I feel pretty confident that they were the right parts and of high quality.

What could I have done that would make it run rough again? I was very careful when installing the new distributor cap to put the plug wires back on in the correct location, even looking up the firing sequence and verifying that it matched the way the plug wires are attached.

Any help would be appreciated.

Thanks,

Jeff

Did you ever figure out what the problem was? I am interested to know since my Monsoon 340 starting to run a little rough.

Link to comment

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.

×
×
  • Create New...