Journey back from an engine disaster...

[Vettedrmr]

Thanks, I'll drop it in. BTW, I don't have any sensors in the thermostat housing. And yes, the mechanical installation of the distributor to TDC is the concern I have; no work was done to verify that at the shop, other than a quick inspection of the general position of the rotor. I'm away from the boat for about a week, going to get back on it when I get back in town.

Thanks for the direction/advice, and have a good one,
Mike

[Vettedrmr]

boatwakes, is there any kind of procedure for indexing the distributor to TDC #1? I don't have any service manuals for this engine.

[boatwakes]

Hey Mike!! Sorry, fun weekend at the lake and no phone!!! I still need to know which distributor you have so post a pic. If it has the crab cap, those are actually called HVS (high voltage spark) units. Basic procedure to set TDC firing #1 (This procedure will work for regular distributors too, you just have to set base timing per manufacturing specs after getting it to run...usually 8*BTDC on fuel injected units with timing lockout engaged and 10* for carbureted with Mercruiser Thunderbolt):
- Remove the number 1 spark plug
- Disconnect the 4 wire connection to the ignition coil and its ignition module (disconnect the purple positive wire on regular ignition coils and the white and red harness for Delco style distributors)
- Turn the engine over (no water needed for this procedure) and pay attention to the sound of the rotation, noting when you hear the "high spot" in it. This is the sound of the open plug hole/no compression.
- Get the rhythm of the high spot for a few rotations and let off the key just before it, the timing mark on the balancer should now be really close to TDC. Remove the rest of the spark plugs (to help ease rotation) and manually rotate the motor (CLOCKWISE ONLY while looking at the front of the engine) using a 5/8" socket and wrench on the balancer bolt to line up the balancer timing mark with the notch on the timing chain cover.
- Pull the distributor cap and note its location to the #1 terminal INSIDE the housing (I mention this because the CRAB CAP terminals inside are connected to their respective cylinders through routing in the cap. Each terminal is labeled EXTERNALLY so use caution when observing the location of the terminal on the CAP and its corresponding cylinder.)
- The distributor rotor turns clockwise as you look down at it so if the rotor is AFTER the #1 terminal, the timing is advanced. Conversely, if the rotor is BEFORE the #1 terminal, it's retarded. SPECIAL NOTE: with the crab caps, there is usually only about 10* rotation of the installed distributor available due to intake manifold clearance and some (Volvo Penta for example) lock the hold down to the distributor body and there is NO rotation available. So keeping that in mind, pull the distributor as required, adjust the rotor as required and reinstall so the rotor terminal is as close as possible to the #1 terminal.
- Re-install the spark plugs and connect the 4 wire harness at the ignition coil/module.
- Start the engine and verify correct idle. If idle is smooth, rev in neutral past 2800 to verify correct high speed timing. You can use a timing gun to watch what the timing does as well but it should be slightly advanced at idle and not above 32* past 3000rpm.

[Vettedrmr]

Thanks. I'm actually waiting on a connecting flight heading home from my son's wedding (it was awesome!). Yeah, I have a crab cap, and rotation is really limited. I'll get to work on it this coming weekend; I'll let you know what I find.

BTW, are you familiar with the TechMate Pro diagnostic tool, and if it's compatible with Diacom ports? May have a line on one and would really like to have something I could monitor the engine with.

Have a good one,
Mike

[boatwakes]

I used to have a TechMate until it got stolen. All the Diacom adapters plug in to its cable. Decent for older applications but not great for monitoring multiple sensors because you can only monitor one at a time on its screen.

[Vettedrmr]

Thanks. Looks like I got scammed out of $100 (partial payment), but not all is loss because I learned there *are* diagnostic scanners out there other than Diacomm. Are there any you'd recommend to a DIY'er?

[boatwakes]

We use Diacom software and I have no complaints but also no experience with any other brands other than OEM. On your engine, there's really not anything we couldn't diagnose without using the software. Temp, oil pressure and trans temp are the usual alarms and failed IAC valves usually won't let the engine start without throttle applied and fuel pressure is a mechanical connection. No real need for it unless you want to see what real time data is happening while the engine is running.

What are you looking to monitor?

[Vettedrmr]

Well, right now the only parameter I would normally be able to monitor that I can't is engine temperature, due to my center LCD display being failed. But I do darn near all of my own mechanical work, and I'd like to be able to monitor for diagnostic codes. Heck, the Tige "owner manual" doesn't even show alarm displays.

[Vettedrmr]

I am SO glad to be making this post! After almost 2 months of engine diagnostics, purchase, R&R, and ignition timing debugging (boatwakes, it was WAY off), today we got the boat on the lake!!! Woo Hoo! I had a friend offer to bring his fishing boat to use as a safety chase, which fortunately wasn't needed as a rescue boat. We put about an hour on the engine, mixing up cruising and some stops and starts (no engine shutdowns). She just ran, well, normal (yay!). Since my center display is dead, I used an infrared sensor to check the temps. Coolant temps were right at the thermostat temp regulator (still the 140, just ran out of time to swap in the 160; that's happening this week), oil pan temps were right around 205.

Got the oil draining now, a total of 1.7 hours on it. Oil doesn't show any "sparkles", although I'm sure if I had it analyzed it would have quite a bit of metal in it. Next oil change will be after 5 hours of use.

Y'all have a good one,
Mike

First run.jpg

[boatwakes]

Well done!!!

[Vettedrmr]

Just to finish this thread out, I changed the oil out with about 1.5 hours on it. Next oil change will have 5 hours on it, then 10, then 25 (or annually, whichever comes first). boatwakes, I got the t'stat changed out, so should be ready to go.

Thanks for all your support and help, and have a good one,
Mike

[Vettedrmr]

Well, I thought this thread was done. Yesterday we took the boat out for the first real fun run, and I've seen now a couple of times something that I think the engine is telling me to adjust. After a period of idling, accelerating the boat normally will occasionally (more than seldom, but not regularly) cause a pop, similar to an old style backfire.

boatwakes, is this a timing or fuel issue? I'm assuming timing, and I *think* it's a bit too advanced. The engine doesn't fall on its face above 3000 rpm (I've been running around 3200, 27 mph for cruise), so I don't think it's too retarded. Or is it some kind of fuel issue? We cleaned-ish the injectors as part of the new engine install, but it was an ultrasonic bath, followed by blowing some air through them while the pintle was retracted with a 9 volt battery. Nothing more than that.

Thanks again for all your help, and have a good one,
Mike

[boatwakes]

Backfires are spark introduced at the wrong time, either exhaust or intake. If its coming out the throttle body, it's likely too advanced and if it's from the exhaust, it's retarded. However, the injectors could also be the culprit if there's one or more not closing completely and allowing excess fuel in the intake port. Because it's intermittent after idling, I'd look at the injectors first. Put a pressure tester on the rail, turn the key to on but not start it and let the fuel system prime. Watch the pressure gauge advance and then it should come to rest after the pump shuts off. The needle should remain steady and it should take several minutes before the pressure drops. If you see the needle drop more than 5 psi in a minute, you've got 1 or more injectors that need to be cleaned.

If the fuel pressure stays constant, rotate the distributor what little you can, clockwise and see if that helps.

[Vettedrmr]

Thanks for the direction. It sounds like it's backfiring through the intake, and you confirmed my thoughts that the timing is too advanced. We checked the fuel pressure as part of our initial checks, and it was solid, *then*. Since that time we cleaned the injectors, so it's a good idea to check the pressure again.

Thanks again, and have a good one,
Mike

[Vettedrmr]

Update: I tested the fuel pressure, started at 48-49 psi, after 10 minutes it was 45 psi. I figured that was pretty good for a problem that shows up while the engine is running, so I've retarded the timing a bit (how's that for scientific?); I'll let you know how it works after our next run this coming Monday.

Have a good one,
Mike