User Tag List
Thanks: 0
Likes: 0
Results 1 to 15 of 21
Thread: 1998 mercury 300 pro max
-
06-30-2014, 04:56 PM #1
5000 RPM
- Join Date
- Oct 2002
- Location
- tappahannock, va
- Posts
- 741
- Thanks (Given)
- 0
- Thanks (Received)
- 1
- Likes (Given)
- 3
- Likes (Received)
- 1
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
1998 mercury 300 pro max
Got a 1998 300 pro max won't go over 3000 rpms. Compression good, spark is good,just had injectors clean last year. Fuel pressure good. Everything looks good on DDT. While running Pull spark plugs wires#3 and 5 motor dies down,1,4,6 you can hear it pop when you put the plugs back on.#2 nothing. Change injector around and nothing change. Any ideas
-
06-30-2014, 05:36 PM #2
Supporting Member
- Join Date
- Oct 2004
- Location
- California
- Posts
- 3,729
- Thanks (Given)
- 1741
- Thanks (Received)
- 424
- Likes (Given)
- 15477
- Likes (Received)
- 4060
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
What spark plugs you runnin?
Wriggleys gum makes me think of boating, "Double your engines, Double your fun"
-
06-30-2014, 06:14 PM #3
5000 RPM
- Join Date
- Oct 2002
- Location
- tappahannock, va
- Posts
- 741
- Thanks (Given)
- 0
- Thanks (Received)
- 1
- Likes (Given)
- 3
- Likes (Received)
- 1
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
Champion ql77cc
Originally Posted by NICE PAIR
-
06-30-2014, 06:22 PM #4
Supporting Member
- Join Date
- Oct 2004
- Location
- California
- Posts
- 3,729
- Thanks (Given)
- 1741
- Thanks (Received)
- 424
- Likes (Given)
- 15477
- Likes (Received)
- 4060
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
Is the problem on the hose or with a load on it? are the plugs new or they last seasons? I was hunting for some issues on mine and it went all squirrely with the wrong champions in it. Went back to ql77cc ran ok.
Wriggleys gum makes me think of boating, "Double your engines, Double your fun"
-
06-30-2014, 06:30 PM #5
5000 RPM
- Join Date
- Oct 2002
- Location
- tappahannock, va
- Posts
- 741
- Thanks (Given)
- 0
- Thanks (Received)
- 1
- Likes (Given)
- 3
- Likes (Received)
- 1
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
Put new plugs in after it started acting funny. Put the same kind that was in champion QL77cc . And yes , under a load
-
06-30-2014, 06:36 PM #6
Supporting Member
- Join Date
- Oct 2004
- Location
- California
- Posts
- 3,729
- Thanks (Given)
- 1741
- Thanks (Received)
- 424
- Likes (Given)
- 15477
- Likes (Received)
- 4060
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
If your compression is good on all 6, it's either fire or fuel. hows the reeds?
Wriggleys gum makes me think of boating, "Double your engines, Double your fun"
-
06-30-2014, 06:56 PM #7
5000 RPM
- Join Date
- Oct 2002
- Location
- tappahannock, va
- Posts
- 741
- Thanks (Given)
- 0
- Thanks (Received)
- 1
- Likes (Given)
- 3
- Likes (Received)
- 1
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
The compression and leak down is good , fire on all 6 , changed the injectors samething Originally Posted by NICE PAIR
-
06-30-2014, 07:39 PM #8
Supporting Member
- Join Date
- Oct 2004
- Location
- California
- Posts
- 3,729
- Thanks (Given)
- 1741
- Thanks (Received)
- 424
- Likes (Given)
- 15477
- Likes (Received)
- 4060
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
Is it missing @ 3000 when it lays down or does it just stop pulling like its running out of fuel? Originally Posted by big poppa pump
You might want to get your manual & DDT and do a static check on all your coils (there is a pretty thorough test procedure in either the merc 3 litre manual or the DDT manual. I'll try and find it tomorrow. Trouble shooting the 3 litre is kinda a pain.Wriggleys gum makes me think of boating, "Double your engines, Double your fun"
-
07-01-2014, 02:33 AM #9
5000 RPM
- Join Date
- Mar 2006
- Location
- auckland new zealand
- Posts
- 655
- Thanks (Given)
- 3
- Thanks (Received)
- 9
- Likes (Given)
- 6
- Likes (Received)
- 13
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
good old stator can you get your hands on one to try had many break down when hot etc
-
07-01-2014, 07:15 AM #10
5000 RPM
- Join Date
- Oct 2002
- Location
- tappahannock, va
- Posts
- 741
- Thanks (Given)
- 0
- Thanks (Received)
- 1
- Likes (Given)
- 3
- Likes (Received)
- 1
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
it started off not doing anything when it go to 3000 rpm, but now, it will sometimes get to 3000, or just die after giving it gas. pressure gauge showed 34-36 lbs the whole time. checked the shift kill switch , that was fine...everything looked fine on DDT, every now and then the #8 would light up (break in mode) when boat cut off.
-
07-01-2014, 08:23 AM #11
Supporting Member
- Join Date
- Oct 2004
- Location
- California
- Posts
- 3,729
- Thanks (Given)
- 1741
- Thanks (Received)
- 424
- Likes (Given)
- 15477
- Likes (Received)
- 4060
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
Is this a salt water motor? Even if not, you might want to check all of your grounds on your motor. fuel computer, ign. computer, etc.
I'm lucky (or un-lucky) enough to have a pair on the same boat, so I usually just switch parts until I find the problem. Take a look @ the pistons, the amount of fuel or lack of might lead you towards your issue. What you are describing could be either fire or fuel.Wriggleys gum makes me think of boating, "Double your engines, Double your fun"
-
07-02-2014, 08:26 PM #12
Supporting Member
- Join Date
- Oct 2004
- Location
- California
- Posts
- 3,729
- Thanks (Given)
- 1741
- Thanks (Received)
- 424
- Likes (Given)
- 15477
- Likes (Received)
- 4060
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
Did you see this? I don't know what is in the 3 litre fuel ecu, is this a possibility?
http://www.screamandfly.com/showthre...to-reload-themWriggleys gum makes me think of boating, "Double your engines, Double your fun"
-
07-03-2014, 01:15 PM #13
Supporting Vendor
- Join Date
- Jun 2004
- Location
- port st. lucie, fl
- Posts
- 5,737
- Thanks (Given)
- 18
- Thanks (Received)
- 51
- Likes (Given)
- 657
- Likes (Received)
- 491
- Mentioned
- 1 Post(s)
- Tagged
- 0 Thread(s)
Those engines were notorious for weak/ bad stators that sometimes the ddt test won't pick up. Try running it up to the point it starts to run crappy kill the ignition and pull the plugs and see if they all look the same. I had a similar issue with one, all tests came back normal, turned out to be a bad stator. Also one bad cdm can drag the whole ignition system down but yet that bad one still has spark. Try unplugging 1 cdm at a time and driving the boat see see if it gains power from any 1 disconnected
Last edited by mrcrsr; 07-03-2014 at 01:23 PM.
action mobile marine, 772 528 0754, dealers for aces fuel products,wolf efi, pro marine,latham and gaffrig/livorsi. we build gearcases and modify them(3 litre) to ratchet, and powerheads as well. 21 skater/3 litre wolf efi 113 mph the engine build http://www.screamandfly.com/showthre...-3-litre-build
-
07-05-2014, 10:56 AM #14
5000 RPM
- Join Date
- Oct 2002
- Location
- tappahannock, va
- Posts
- 741
- Thanks (Given)
- 0
- Thanks (Received)
- 1
- Likes (Given)
- 3
- Likes (Received)
- 1
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
Pull the plug wires on #1,2,4 like there dead ,change injectors and it has spark on all .same thing
-
07-05-2014, 08:14 PM #15
8000 RPM
- Join Date
- Apr 2001
- Location
- Western Pennsylvania
- Posts
- 3,882
- Thanks (Given)
- 48
- Thanks (Received)
- 92
- Likes (Given)
- 184
- Likes (Received)
- 378
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
I have 6 coils from when I had my 1998 300 Promax if interested. I'm open for offers?
Checkmate 2002 Convincor 270 496 MAG-HO
2003 Cougar 22MTR w/300xs SOLD
90 21Skater w/300xs - sold
98 STV Euroski w/280 - sold
2006 Trailblazer SS 6.0l 395hp
Reply With Quote
