MarineEngine.com - Your online store for all types of marine engines and boat parts.
PHONE ORDERS
Monday - Friday
9:00 AM - 5:00 PM EST
Click for TOLL-FREE Number
Online Checkout
Special $9.95 Flat Rate Shipping
(800) 209-9624 | Home | Contact | Shipping | Returns | Cart View your shopping cart.
Part Number Search
Shop by engine/drive part number.
Original & matching parts for sale.
Manuals & Accessories
Shop by description, item number
or manufacturer's model number.
Boat Repair Forum Boat Repair Forum   Boat Video Gallery Video Gallery
   
Results 1 to 14 of 14
  1. #1

    Question Timing Problem on Thunderbolt V

    Here is the background....Bought a 94 Crownline 225br with a rusted up engine due to the plug being left in it, serial #OF354207. Rebuilt the engine, new fuel pump, and cleaned the carb. Finally got it started after getting the distributor lined up correctly. Brought it up to temp, oil pressure runs around 40psi at idle, compression after break-in is at 150 psi on all cylinders. My issue started after if fired the first time. It cranked fine until it started then after that it will kickback like crazy and then eventually the engine will start and run fine. I thought it was a starter alignment/flywheel issue but after two days of shimming there was no change. I had noticed that the voltage gauge would jump every time the hour meter ticked and the voltage gauge dropped while revving. I put in a different battery and cleaned the starter circuit connections with no change. Then, I hooked my VOM to the yellow/red wire to check voltage while cranking (10.3V) with the coil wire unplugged and it cranked just fine...verified with multiple attempts. Hooked the coil wire back to the distributor and it is grinding and skipping again. I got it started, checked and it is timed at 10 deg. BTDC per the sticker on the engine cover. I reset it to 8* per the manual for thunderbolt v. Pulled the coil wire again and it cranks just fine.

    What I don't get is why the it will time in base mode to 8* and when returned then to normal mode the idle sounds great and the throttle is snappy. But when I go to start it, it is hard to start and kicks like crazy. When I put my timing light on it and revved up it up to 1750 rpm the timing was at 4* BTDC...it bounced around a little but for the most part it stayed at 4*. I know it won't be at full advance but it should have been off the timing mark. I unplugged the knock module with the engine off and then started it to check voltage to the module with it running and it made no difference at all, I unplugged the knock sensor and no change. When I checked the voltage at the timing lead it is anywhere from 4-5.5 but not 8-10 like it should be. It seems like the timing is getting advanced during startup...is this possible? Could it be a combination of the knock and ICM? Does the timing lead voltage have any correlation to ignition timing?

    I have moved the timing all over the place and it is crazy but it will start best with no kickback and as soon as you hit the key at 8* ATDC?? Sorry for the long winded post....just trying to give all the details

  2. #2

    Default Re: Timing Problem on Thunderbolt V

    Anybody???

  3. #3
    Join Date
    Aug 2006
    Location
    SW Ohio, USA
    Posts
    10,328

    Default Re: Timing Problem on Thunderbolt V

    By "kickback" do you mean it tries to run backwards? Have you followed Merc's procedure for setting the base timing? Since the timing is changing on its own there seems to be an electronic issue.
    I had noticed that the voltage gauge would jump every time the hour meter ticked and the voltage gauge dropped while revving.
    The hr meter is just a set of geared dials driven by a synchronous DC motor...there may be a loose elec. connection in it. Check all of the wiring in the charging circuit for corrosion...something is drawing down the alt. output while revving...may need to have the alt. tested at a rebuild shop.
    Fix minor things (replace wear items for preventative maintenance.) that cause major problems before they break.

  4. #4

    Default Re: Timing Problem on Thunderbolt V

    Changed my opinion can't leave it blank
    Last edited by Master mechanic; 10-12-2012 at 02:03 PM.

  5. #5
    Join Date
    Dec 2006
    Location
    Chaumont Bay, N.y., USA
    Posts
    4,225

    Default Re: Timing Problem on Thunderbolt V

    Quote Originally Posted by iaff284 View Post
    Here is the background....Bought a 94 Crownline 225br with a rusted up engine due to the plug being left in it, serial #OF354207. Rebuilt the engine, new fuel pump, and cleaned the carb. Finally got it started after getting the distributor lined up correctly. Brought it up to temp, oil pressure runs around 40psi at idle, compression after break-in is at 150 psi on all cylinders. My issue started after if fired the first time. It cranked fine until it started then after that it will kickback like crazy and then eventually the engine will start and run fine. I thought it was a starter alignment/flywheel issue but after two days of shimming there was no change. I had noticed that the voltage gauge would jump every time the hour meter ticked and the voltage gauge dropped while revving. I put in a different battery and cleaned the starter circuit connections with no change. Then, I hooked my VOM to the yellow/red wire to check voltage while cranking (10.3V) with the coil wire unplugged and it cranked just fine...verified with multiple attempts. Hooked the coil wire back to the distributor and it is grinding and skipping again. I got it started, checked and it is timed at 10 deg. BTDC per the sticker on the engine cover. I reset it to 8* per the manual for thunderbolt v. Pulled the coil wire again and it cranks just fine.

    What I don't get is why the it will time in base mode to 8* and when returned then to normal mode the idle sounds great and the throttle is snappy. But when I go to start it, it is hard to start and kicks like crazy. When I put my timing light on it and revved up it up to 1750 rpm the timing was at 4* BTDC...it bounced around a little but for the most part it stayed at 4*. I know it won't be at full advance but it should have been off the timing mark. I unplugged the knock module with the engine off and then started it to check voltage to the module with it running and it made no difference at all, I unplugged the knock sensor and no change. When I checked the voltage at the timing lead it is anywhere from 4-5.5 but not 8-10 like it should be. It seems like the timing is getting advanced during startup...is this possible? Could it be a combination of the knock and ICM? Does the timing lead voltage have any correlation to ignition timing?

    I have moved the timing all over the place and it is crazy but it will start best with no kickback and as soon as you hit the key at 8* ATDC?? Sorry for the long winded post....just trying to give all the details
    Ayuh,.... My guess is, ya Didn't get the distributer in right, 'n the Firin' Order is Wrong....

    I'm guessin', you've got 2 or more plug wires crossed....
    Any Grease is Better,... Than No grease at All....

  6. #6
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    7,314

    Default Re: Timing Problem on Thunderbolt V

    Bill, if he had plug wires crossed, I think this would not be so.
    Quote Originally Posted by iaff284
    It cranked fine until it started then after that it will kickback like crazy and then eventually the engine will start and run fine.
    iaff284, the EST (electronic spark timing) distributor offers ZERO "progressive" advance in and of itself.
    The EST controller itself sees full spark advance, and then through the electronics and algorythm of the controller unit, the system delays the spark event as per engine RPM.
    If equipped with the knock sensor, this too has an influence on the algorythm, and will make changes to the delay.

    The "initial" advance is simply a function of the distributor housing's indexing with the camshaft and crankshaft, and of course while in BASE mode, BASE advance is set, and then the system is returned to run mode.

    If the control module is going whacky on you, then your actual spark lead may not be consistant... and may be irratic.

    I would try another module, and see if it corrects the problem.

    Better yet, get rid of that TB system altogether!



    .
    Last edited by RicardoMarine; 10-13-2012 at 12:39 PM.
    Rick ... aka Ricardo
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

  7. #7
    Join Date
    Oct 2011
    Location
    maplevalley WA
    Posts
    7,998

    Default Re: Timing Problem on Thunderbolt V

    You say it starts best at 8 atdc is it me that just dont sound right. I wouldnt run it very much until you get the timing advance curve correct for that engine. Is it a hall effect distributor the module will advance the timing with rpm and the knock sensor/s retard the timing when detonation is present try tapping on the block next to the knock sensor with a wrench and see if the timing retards, do not tap on the knock sensor itself they are real sensitive. Knock sensors are torque sensitive also put a good thread sealer on the threads and torque it to spec or it will give you a false signal. Are there two knock sensors for your engine something to look into.

  8. #8

    Default Re: Timing Problem on Thunderbolt V

    Bondo, I had thought the spark plug wires could be crossed and I traced them and they were correct and then replaced them with a new set and are correct. I had thought that maybe the Dist. was off a tooth but if that was the case I should not be able to see a timing mark as it would be up to 16 deg out and if it did start it would run like crud...currently once it starts it revs and idles great...My thoughts where that maybe the knock sensor/module is bad and is pulling the 8-10 deg of timing all the time....or the EST is going hinky with a low voltage issue on startup (due to the other electrical issues being present). The other question is could the timing chain be off a tooth? Would it run well if it was off a tooth? The only other issue that I could think of that could be causing a preignition issue is if the carb is running way rich....When I started it up to winterize it was running way rough and with alot of black smoke until it warmed up, which could be the choke....I am at a loss!!

    Rick, I am interested in removing the TB system altogether....any recommendations? I don't know where I am going to find a module to test with. I had debated on temporarily putting on an HEI system (with the hatch open and only to see if it is the EST module).

  9. #9
    Join Date
    Jul 2008
    Location
    Northboro, Ma, USA
    Posts
    3,488

    Default Re: Timing Problem on Thunderbolt V

    Replacing the igniotion is not the answer YET.

    You need to understand what is wrong first.

    Are you sure it is ignition related? A timing module "typically" cause a bad running condition as it does not advance the timing or cause a rough running motor. It typically does not cause a out of timing start up condition, Again typically,

    A out of time start condition would indicate to me a possible bad timing chain, if the chain has a lot of slack it could act as if it was a tooth off.

    that bieng said,

    Make a remote starting rig and disconnect the main harness connector from the engine mount.

    you need 2 switches, one is a momentary and the other a on/off. also need 4 ft each of 12 guage wire, RED Yellow and purple and three good alligator clips for the ends.

    Wire two of the switch contacts together and attach a RED 12 guage wire to it with a good aligator clip on the end. this will go to Battery +

    Attach the yellow to the momentary (open contact) and purple to the on/off (open contact).

    Connect the yellow alligator clip to the slave solenoid at the small yellow with red wire connection (coil of solenoid).

    Connect the purple to coil +

    turn the on/off on, hit the momentary to crank engine, when it starts let go of the momentary. To shut engine off turn off the on/off.

    This will eliminate any elictrical gremlins from the dash area it will also put battery voltage to the coil.

    If this starts the engine with no issues several times both hot and cold then you have an electrical issue.......if not then more diagnostics is needed.

    Once started put the timing light on the balancer, watch the timing mark and let us know what it does exactly,

    Disconnect the spark knock wire and redo timing watch and let us know what it does,

    If the timing mark is jumping around with the spark knock wire disconnected then I would say timing chain.....


    Has this boat seen any hydrolock issues in the past that you are aware of? this destroys timing chians...

    Quote from service manual

    The knock control module conatins a solid state circiut which monitors the knock sensors AC voltage signal and then supplies 8-10 volt signal to the ignition control module. It is extremely important to have the corect knock module and or sensor for the specific application.
    The knock module (piggy backed on the timing module on the distributor) is powered by the 12 volts from the ignition switch/curciut Terminal B on the module. If the 12 volt source is not present (TERMINAL B) then THE KNOCK MODULE CANNOT SEND THE 8-10 VOLTS TO THE TIMING MODULE AND A FALSE SPARK RETARD WILL RESULT. Also if the knock sensor wire is too close to ignition wires it can cause a false signal...

    My take is if the knock sensor wire is removed it keeps the 8-10 volt signal on the knock module and thus the timing control module will work with no retard function if knock is present in the motor. In other words just like a TB IV.

    So check for Battery voltage at knock module pin B when running and when just ignition switch is on and not running (or with remote rig connected)
    Remeber if you use the remote rig disconnect the big wire harness connector to isolate the engine wire harness from the dash.

  10. #10

    Default Re: Timing Problem on Thunderbolt V

    Kghost, The ignition setup is a great idea, unfortunately the temps dropped the other day and I had to winterize. When I was playing with the timing I had checked voltage on the timing lead that should have 8-10 volts when the knock wire was disconnected and it showed anywhere from 3.5-5.5 volts. I had the knock sensor wire unplugged and when in base timing mode the timing mark was moving around + or - 3 deg. As for the hydrolock, the engine was rusted solid when I got it and the previous owner had tried breaking it loose with a breaker bar on the crank bolt. I can't speak as to wether or not it hydrolocked as I am pretty sure the water came in through the carb when they left the plug in the bilge.

    In March I am going to try the remote rig and see what happens. If the chain is off a tooth would it run good after started?

  11. #11
    Join Date
    Aug 2006
    Location
    SW Ohio, USA
    Posts
    10,328

    Default Re: Timing Problem on Thunderbolt V

    I had checked voltage on the timing lead that should have 8-10 volts when the knock wire was disconnected and it showed anywhere from 3.5-5.5 volts.
    Since the engine was submerged that wire may have a high resistance corroded spot. Trace the wire and check the voltage on the other end.
    Fix minor things (replace wear items for preventative maintenance.) that cause major problems before they break.

  12. #12
    Join Date
    Jul 2008
    Location
    Northboro, Ma, USA
    Posts
    3,488

    Default Re: Timing Problem on Thunderbolt V

    Send me a personal message with your phone number and when to call and We can discuss
    this. i hate to type pages....

  13. #13

    Default Re: Timing Problem on Thunderbolt V

    Just an update to close out the thread..... After dewinterizing I followed KGhost's idea with the remote ignition and it started fine, indicating a problem in the dash wiring. After cleaning all the connections and repairing a loose wire in the main electrical harness under the dash, the engine starts and runs great. Thanks to everyone for thier advice and especially KGhost for taking the time to talk on the phone to help troubleshoot the possible problems!!!!!

  14. #14
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    7,314

    Default Re: Timing Problem on Thunderbolt V

    Kudos to you for getting it repaired and for updating your thread, and a Big Kudos to Kghost for helping you via a phone conversation!


    .
    Rick ... aka Ricardo
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

Similar Threads

  1. 1983 Thunderbolt iv ignition amplifier problem?????
    By Axeheum in forum Mercruiser Sterndrive Forum
    Replies: 3
    Last Post: 06-17-2011, 09:05 AM
  2. Thunderbolt IV timing question
    By 87concord in forum Mercruiser Sterndrive Forum
    Replies: 19
    Last Post: 06-04-2011, 11:08 AM
  3. 9.8 thunderbolt wiring problem help much appreciated
    By destroyer28a in forum Mercury Mariner Outboard Forum
    Replies: 3
    Last Post: 05-13-2011, 08:37 AM
  4. 1988 Mercruiser 57L thunderbolt timing
    By paul59 in forum Mercruiser Sterndrive Archive
    Replies: 11
    Last Post: 10-13-2008, 10:15 AM
  5. Mercruiser 57 LX Thunderbolt idel and timing problems
    By duke in forum Mercruiser Sterndrive Archive
    Replies: 6
    Last Post: 07-31-2006, 08:02 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •