Mercruiser 888

[dklortie]

Hi all,
I think that I have my prop issue solved, now for the next conundrum. I wanted to make sure that the lack of RPM is the prop being overpitched and not that the engine adjustment out a bit. I checked the dwell and it is at 30.1 degrees, so that checked out alright. Next I looked on the intake for the number 1 cylinder. The casting on the intake shows the #1 cylinder as the front left cylinder when looking at the flywheel. Hooked the timing light up to it and could not find the timing mark. Looked in my selock manual and it shows that the cylinder I hooked the timing light up to is the #1 cylinder. I decided to move the timing light trigger to what is marked on the casting as the #5 cylinder. Voila the timing light shows the timing mark dead on at 30deg. I then took the trigger and moved it to what would be the #6 cylinder assumig that the front right is #1 according to timing light and timing mark shows up at 30deg. The problem is that the cylinder is shown on the casting as #2. The engine is running alright, so ???? A couple of spots I checked on the internet correspond to my manual and the casting #'s on the intake. So it would look like this:

Marked on intake and in the selok manual:

4 8
3 7
2 6
1 5
front (flywheel)

What I am finding:

8 4
7 3
6 2
5 1
front (flywheel)

I am so confused. Add on top of that I am being told that there are two firing orders 1-3-.... and 1-5-....?

Am I donig something wrong, or should I have a beer and try this again? I just don't know why the casting would show that the front left is # 1, but the timing mark is spot on on what is marked as # 5 on the front right of the intake. If they were wired up incorrectly ie. wires swapped from one side to the other, how could the engine even run?

Any help or insite into this would be greatly appreciated.

 

[timing_ca]

Re: Mercruiser 888

hi welcome to iboats. If you look at the top of the main page you'll see for adults only, there you'll find the mercruiser manual. Check there for the firing order.

 

[dklortie]

Re: Mercruiser 888

Hi Timing.
I have looked at both the selok and the merc manual # 2 on boatinfo.no. Both show the # 1 cylinder as the front left when looking at the flywheel. Going by that and moving the timing pickup to each plug wire, it would be cylinder 5 and 2 as the 30deg according to the timing mark. Would make sense if the left and right #'s were swapped from side to side meaning 1 & 6 which should be the first and 5th in the firing order. I am not a drinker, but this new boat is quickly making me an alcoholic.

 

[Don S]

Re: Mercruiser 888

The flywheel is on the back of the engine, not the front.
Looking at the flywheel, the engine turns counter clock wise (aka LH Rotation)
The distributor is on the front of the engine on Fords.
This is the firing order for the 888

 

[dklortie]

Re: Mercruiser 888

Hi Don,
Sorry for my terminology. The picture that you show is what all the information that I am finding has. And yes, when I say the front of the engine, I am meaning the side toward the bow of the boat which has the distributor so it would mean that i am standing at the top of the page and looking down at the picture. The problem that I am having is what is labeled as # 5 and 2 are what I am getting the timing light to show the correct ignition timing (like the left and right sides were swapped). This is why I am getting so confused. If you are looking at the picture above, 5 & 1 are swapped, 6 & 2 are swapped, 7 & 3 are swapped and 8 & 4 are swapped. Leave it to me to find something that just defies all logic.

 

[Don S]

Re: Mercruiser 888

What probably happened is someone took the distributor out, then when they put it back in, they didn't have the rotor in the same location. Not a problem, as long as you move the wires to the new #1 position. It just means your #1 is in a different location on the cap than shown in the manual. Not a problem at all.

Follow the spark plug wire from the #1 spark plug (front/starboard) and follow it to the distributor cap. That is now number one on the cap, run your firing order from there.

 

[dklortie]

Re: Mercruiser 888

Thanks Don,
What I am wondering though. Is the timing mark lines up on cylinder #5 & 2. The engine is running but if you look at the prop forum, I found that the prop is overpitched for the boat. Currently a 19 cupped and according to the manual it should be a 15 pitch cupped. RPM at WOT is currently between 2900 and 3000.

I am picking up a 15 pitch prop tomorrow to put on the boat, but wanted to make sure that the engine itself wasn't part of the problem with the low rpm and the engine lugging. I changed out the spark plugs (one wire off at a time), and the old plugs were blacker than I had ever seen. I attributed it to the engine lugging badly because of the overpitched prop and low rpms. Now I am starting to worry that there may be some major engine trouble in my future.

When I put the timing light on the #1 front/starboard cylinder, the timing mark did not line up at all. If I move the wires around to make # 1 cylinder and route from there to the firing order, will I cause a problem with the engine running, or do damage to the engine in any way. Also, will that mean that I am going to have to do a major retiming to get the timing mark back to the #1 cylinder. With the timing light on # 1, if I assume that 1-4 is on port and 5-8 on starboard (the way it shows as 30deg. advance), when I moved the wire to what would be # 6 but is actually 2 (5th in the firing order), the timing mark lines up again. I am just worried that I might be getting in over my head here when the engine is still running.

The situation that you are describing, could that be part of the reason for the low rpm and the engine seeming to be lugging?

I think what is causing me trouble to understand, is it seems like the cylinder numbers have switched sides on the engine. If I use # 5 as 1 (currently aligned timing mark), and 6 is the # 2 cylinder as the 5th in the firing order, when I move wire to 1 as 1 and follow the order from there, that would mean that the fifth in the firing order after the # 5 cylinder should be 3, where it seems to go from 5 to 2 the way the timing mark lines up right now.

Sorry if I seem to be going around in circles. We just got the boat a month ago, and do not want to have to get into a summer long repair before getting back out again.

 

[Don S]

Re: Mercruiser 888

It's a 4 stroke motor. That means the crankshaft goes around 2 times for every one round of the distributor. So at 180? of the distributors rotation, the timing mark comes up again on the exhaust stroke of a different cylinder. Google four stroke engines and do some reading.

 

[dklortie]

Re: Mercruiser 888

Forgive me Don, I do understand the principals of the 4 stroke engine and it being 180 degrees out of for the distributor. What I guess I missed from your earlier post, is are you saying to move the wire for spark plug 1 to the port where it lines up with the timing mark on the distributor (ie. move the wire from where it is on the distributor to the port that is currently supplying cylinder # 5) and then follow the firing order around the distributor cap, or should I rotate the distributor cap around until the timing mark lines up with where the # 1 cyliner is plugged in now and follow the firing order from there?

Please forgive me.

 

[Don S]

Re: Mercruiser 888

Lets do this. Find #1 TDC on the compression stroke. Here is how to find it http://forums.iboats.com/showthread.php?t=427081

Once you find it, look at the rotor on the distributor and let me know what postion (letter) the rotor is pointing at.

\
.

 

[dklortie]

Re: Mercruiser 888

Hi all,
Just an update to my earlier post. Thanks to all those that responded to my question. To answer Don S.'s comment first, C is top dead centre for the #1 cylinder. Went from there and the wiring is correct. Found out that the timing light that I was lent was bad. Used a different timing light and voila, found out that the timing was out by 3?. So a quick adjustment and all is good again. Also changed out the prop from a 14.5 x 19 to a 16 x 15 pitch and wow what a difference. Went from 3000 @ WOT doing 20mph to 3800 @ WOT doing 38.6mph. Cruise of 3000 rpm has me doing 27.8mph. Not bad for a 188hp engine pushing a 5500lb 26 footer through the water. The engine sounds a lot better as well. Had it out over the weekend and did the same trip as the long weekend. Went from burning over 70 litres to 23 litres this weekend. $100 prop almost paid for in the first weekend.

Thanks again for all the assistance. It is great to know that there are those who have the knowledge and are willing and able to share it with the rest of us.

 

[Eric 3.7LX Alpha 1]

Re: Mercruiser 888

Crazy how the bad timing light had you chasing your tail. Glad you came back on here and shared the fix for others down the road that may be searching this.