View Full Version : Engine timing and back firing

09-27-2009, 07:47 PM
I have a 350 efi and we can't seem to find where to connect the coil clamp on the timing light. We had an issue with back firing that we tracked to a burnt intake valve and fixed that but we do not have the engine timed exactly. It runs ok but back fires at high RPM's and when slowing down. I have been told that it is either a lean pop or timing. Can't get the timing done if I cant get the timing light connected as there are no timing marks on the dampener. I can't seem to be able to find anyone that knows how to correctly time this engine where I live.

09-30-2009, 09:32 AM
distributor system?

09-30-2009, 07:02 PM
"hi Chelsea, just to warn you Im no marine mech. but I do no a little. The timing lite should hook up to pos. and neg. of your battery and to your #1 sparkplug wire. On a 350 when looking from the front should be the closes wire on your right.As far as the dampener they are often hard to see with the paint and all but if you turn it over manually they should be there. Good luck Cam"

10-01-2009, 12:33 PM
Getting base timing seems to be an issue as I can't find anyone that knows how to set it. I tried a gm adapter that plugs into the distributor but it shut off the fuel flow when plugged in. The motor also has an issue when at higher rpms where the timing goes all over the place including stopping and starting. I replaced the distributor already to no avail.
avail and I can't find anyone that knows how to set the base timing or how to work on a EFI engine.

It seems like a sensor issue but which one.

I tried to get help from Marine Power but they don't seem to offer any customer support and the local sales rep. will not return calls.

10-01-2009, 12:36 PM
"One more thing. When we have tried to time it the advance goes up smoothly to a point then goes nuts. Like something is vibrating or loose,l but what I don't know."

10-01-2009, 06:17 PM
what type of dist. did you install? was it new or rebuilt?? Is this a volvo or merc ?? Cam

10-01-2009, 06:49 PM
"Knowing which distributor you have will enable the details for setting the base timing, which is all you can adjust. A picture would help, showing the connector(s) details, if you can't find the model number.

Regarding the timing going nuts, does the engine behave in a simmilar manner? If not, I'd get another timing light.

Sadly, your experience with Marine Power isn't uncommon for a 'second hand' customer, based on what I've heard. Is the local "sales rep" a dealer or distributor?"

10-02-2009, 12:14 AM
The engine goes nuts as well. I am not sure as to the local rep as I can never get a call back. Sales rep is my guess. Can I post a picture here?

I got a tech to time it and read some codes. Code for a tps low voltage and 42 est bypass fault level 2. The latter I don't have a clue on. And I can't get any thing on line about it.

10-02-2009, 07:00 AM
"EST BYPASS is mamrine ecu-speak for the control of the EST (delco) type of distributor. Bypass mode (i think) is the fixed timing mode used before the ECU starts to optimize the timing. Level 2 is a new one on me. Since the distributor has been changed, that only leaves the interconnecting wires and the computer."

10-02-2009, 10:51 AM
Well that is what I am thinking as well. The low voltage at the tbs is where I am going to look next as the wires would lead to that being an issue. We are also rechecking the compression and valve adjustment to make sure that was done correct not to mention checking is the rocker arms move up and down correctly. Thought this seems more of an issue with ignition. I don't know how to check the computer I was hoping the code reader guy would have found out if there was an issue with that.

Argg. I hate engines.

10-02-2009, 03:55 PM
"Which computer is used on that engine? If you don't know which MEFI version it is, describe the connectors and how they attached to the box. If it is a 2 or newer, the 42 indicates the timing (bypass) lead is grounded and may be intermittent (continuity and to ground). May have to remove the harness loom/tape to check that wire its whole length."

10-02-2009, 10:15 PM
Well a valve adjustment did little and trying to find a way to set timing failed so we timed it by hand and played with it and it is running now. I would still like to know how to properly time the engine but event he engine manual doesn't have a real way to time the engine.

10-02-2009, 11:12 PM
"Here's a start:
http://www.marinemechanic.com/site/page229.html ("")

You can buy or mmake the connector if you have access to a weather-packs kit. Some auto parts stores mmay sell them too - tell them you need the connector for a delco voyager distributor.

You can also find many variations by doing a www search on {base tming delco EST}. If time permits on Monday, I'll search a couple Merc Manuals; if I find something worthwhile and small I'll post it."

10-05-2009, 03:30 PM
"Here's a link to another thread that has a link to an OEM manual with drawings:

http://www.themalibucrew.com/forums/index.php?showtopic=12273 ("")

It appears to be wholly consistent with the MERC info I will email separately."

10-06-2009, 12:18 PM
"Found an OEM description of how to set the timing on an EST. this one came from VP. Posted for those that may stumble upon this thread in the future. Original source found on iboats forum.

<!-attachment-!><center>http://www.marineengine.com/discus/icons/attachment_icon.gifest timing""></center><!-/attachment-!>"

10-06-2009, 12:27 PM
"Sorry - had to downsize the attachment

<center><table border=1><tr><td>[img]http://www.marineengine.com/discus/icons/mime_pdf.gif""" align=left alt=""application/pdf"">est timing
Volvo Delco EST timing-150.pdf ("") (40.6 k)</td></tr></table></center>"

10-06-2009, 08:57 PM

Unfortunately we tried that first and the jumper only makes the motor not run. We ended up playing with the timing by hand starting with a the high speed miss and adjusting it till the miss went away then fine tuning it by moving it back till we got a ping when accelerating and putting it between those extremes. We think that the motor was so far out of time that the computer could not compensate. But it runs good now so we don&#39;t want to change anything unless we get a fix for timing it.

All and all we never did get a correct way to time the engine even the service manual&#39;s way doesn&#39;t work.

But thanks for all the help. I wish the Marine Power offered some support for there engines.

Vessel Assist Monterey Bay

11-12-2009, 09:18 AM
"if you have the flat top distributor &#40;wires come in from sides&#41;then you can not set timing. when installing bring motor to #1 tdc compression stroke, there is a little triangle pointing inward on the base of the distributor on the inside, get the rotor to line up with that and your good. computer does the rest"

11-12-2009, 10:08 AM
Regular top distributor.

I could use some help finding a source for the risers they need replacing.

11-17-2009, 10:55 PM
"Ok im more familiar with mercruiser than marine-power, but what i do know is the plug you were trying to use is for the carb set up. There is no computer in the loop for that, its just mechanical w/o the points to where out. On the efi tbi setup you have to tell the computer to stop advancing. some times you have a jumper that you have to unplug, sometimes you have to ground out a diagnostic connector. But none of witch has anything to do with the distributor, you have to tell the computer you want to set the timing.some base timing is 0 some are 8 and some are 10. Now i dont see where you have changed the coil, i have seen them fire ok at idle but miss at higher rpm. this will make the timing move around, ever time the motor misses the weights in the distributor jump moving the timing. also check the wires from the computer to the coil and the distributor, not just the plugs but the wires themselves. I have seen the vibration break the wires where they branch from the mane harness
and go to the distributor and the coil, even the tach wire can mess with the timing, unplug it if you can.
If you can post your model-ser
-dom numbers i can find the correct info for setting the timing. I have the best dealer you can ask for with every factory manual ever made but i need the numbers to look, its a big haystack lol.
Do you have twin engines or single, is the motor original for the boat, if not please do tell what year the boat is. as far as the risers i need to know what drive setup you have. I just finished a marine-power to Volvo drive and went for a custom fit. universal sierra manifolds and risers. Had to cut off the tops of the y pipe and fab new elbows do to the fact that the old suff was 3 3/4 and the new was 3&#34; but didnt have to drill and tap anything for closed cooling and access was improved for getting to oil filter and starter and such do to the design of the manifold. sierra is the best, they cover parts and labor!! warning DO NOT USE OSCO, i have gotten three manifold with thin castings that leaked in less than one year causing major damage to the block and the heads, so i dont buy from them any more"