Mechanical engineer, mechanic, and fuel injection expert on a quest to make marine engines less mysterious and costly. Please subscribe and hit the like button if you’d like to see more of my work!!
Although I have a full time job as a mechanical engineer I do freelance mechanic work as a second business focusing on marine engines. While I’ve rebuilt hundreds of engines (Porsche, BMW, Chevy, Ford, Chrysler, AMC, Nissan, Toyota, etc.) I’ve been rebuilding marine engines for the last five years. For a quote gmefiguy@gmail.com.
I also design, manufacture, and sell parts that I create. See my parts and tools playlist here:
I've been struggling with getting my 1998 mercruiser 305 5.0L carb to start. Pretty much the only thing I haven't touched yet is the ICM. Is there a test I can do to see if it's toast? There has been so many things wrong with this motor as I inherited it from an auction. But, when I finally got it to turn over and idle. It would eventually have a backfire through the carb, and stop. Then, as I started it again, the length of time it idled grew less and less. It was not able to increase in rpm and Rev higher, but that was due to a plugged venturi. I drained the fuel tank of bad fuel. But still that yellow varnish left behind. Psi of fuel pump is at 7 psi. Within range of 3-7 per the manual. I've rebuilt the carb 2x. I've ensured the float is at proper mm distances. I have the idle screw at 1.5 at the moment, though oddly the Manual has 1.25 in another location. I've replaced the ignition coil. Re-lapped the valves, good cylinder psi. I'm feeling utterly defeated here. Not sure where to turn or what to do. Been working on this over a month now. Please help? Edit: I forgot to mention that all it does now, is with starter fluid or not, either way, it's only within the first 3 or 4 first piston ignitions that ignition seems to happen. Then after that, it just turns and turns with nothing happening. I will turn the key off. Wait a second. Then start it again and again, first few pistons fire off - them there is nothing. I don't know what to do. I'm out of my league here. Super frustrated.
Welcome to Thunderbolt Ignition Wonderland. The solution is right in front of you. Do you really think I’d go to all the trouble to create all these videos about replacing the Thunderbolt Ignition for no reason? There is no test, there is no logic you can apply, there is only one solution you can do and that’s replace the Thunderbolt ignition system with a Delco EST ignition. You could try replacing the optical pickup in the distributor since you’ve already replaced the coil. But there is no test for the module. It’s a mysterious beast that will tempt you for weeks by half working and then not working. The link you posted on says it’s obsolete. Follow the link in the description to the more recent Sparkie the Eel playlist to find your way out of Thunderbolt Wonderland.
I might be missing it, but is there a spot in one of the videos that shows the shift kill white/black, and red wire on the harness on the shift kill switch itself, or are they connected together?
The shift kill switch is a micro switch mounted to the shift mechanism. It doesn’t get connected until the shift mechanism is attached to the exhaust after the engine is installed in the boat.
@moccasinmarine thank you, so there is nothing saying where the red wire from the distributer, and the white/black get connected? That's why I was wondering if I missed something in another video...appreciate it.
I know it's not related to this video but My steering is locked up mercruiser 3.0 with steering assist Removed Steering nut Steering wheel. Moves freely. Unhooked. Outdrive from. Steering via Clovis pin. Outdrive moves freely as long as I have The big aluminum tube turnt a certain angle. Cannot take entire steering cable rod out of the aluminum tube It's like it's getting hung up at the end.???
Melonized steel distributor gears are nitrided for wear resistance. Nitriding is a form of case hardening. The item to be treated is heated in a metallurgical oven in an atmosphere of pure nitrogen to form a very hard glass like surface. In the process of heat treatment, areas to be free of nitriding can be painted with masking clay. Cheers
Thanks!- your video saved me a lot of confusion and frustration this evening, attempting to try to adjust the timing on a Volvo Penta 5.0L GXI-J GM block with this distributor setup. Thanks again man.
You can’t adjust the timing on systems using the crab cap distributor. It’s fixed by the crankshaft sensor which is keyed (non adjustable). The distributor still has to be mechanically timed so that at TDC the rotor points to the #1 cap contact. On some applications the distributor clamp is square and locks the distributor in only one position. However, if you have the distributor with vertical posts and a 6 pin module, then you set the timing using the method in this video. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-djjvdJAEdVY.htmlsi=KstJ8JV0TdDiIAxN Thanks for the super thanks btw.
@@moccasinmarine Yepper, that that was why it was so helpful- I learned that there were no adjustments to be made other than proper alignment/indexing during installation. You saved vacation! Thanks again,🙂
Using a melonized gear on a cam not designed for it, is a recipe for disaster. The ignition system used has literally nothing to do with distributor gear choice...... Not a thing...... All camshafts are designed to use a slightly softer gear than the gear on the camshaft. The width of the wear pattern has just as much to do with installed depth, machining tolerances of the block, core shift, etc. As it does gear type as well. The wear on the V6 gear shown, strongly suggests oil pump chatter/cavitation and timing chain slap, you can see it plainly on the gear.... If you are using an aftermarket cam, change the cam, factory cam, etc, use the gear type the manufacture of the cam core recommends. I have had bronze distributor gears last 100k+ on billet cores, steel cores, oe cores, etc, and they are sacrificial gears that last for years.... The wrong gear, will rip one of the gears to shreds, every time..... So will other mechanical issues left unchecked... Suggesting to use the wrong gear in a V6, is an odd choice to recommend, or even promote... The gear will be far harder than the cam, and chew the cam gear to shreds.....
Thanks for your opinion. All gears except where I stated had high miles on them were ran on a brand new engine so no chain slop. The gears are cheap and not intended to last. The 5.0, 5.7, and 6.2 after 1995 all used melonized gears from factory so it is a thing, as can be confirmed by GM. The 4.3 camshaft back to 1987 is also a steel billet roller cam and will benefit from the melonized gear. But you’re right the v6 gears are sacrificial and wear out several times during the life of the engine.
I'm redoing an intake manifold. And before I started tearing it apart. I didn't set it at top dead center. When I took off the intake man, I lifted the distributor out remove the manifold and pop the distributor straight back down into the oil pump. When I reassemble it do you think I can lift the distributor off, Pop the manifold on tighten it down and drop the distributor back in, the same position it was removed in?
@@moccasinmarine I'll try and do it the right way. Just didn't know until this video. Have you ever used one of those cheap raw water pumps from Amazon or ebay?
I was trying to ascertain where the oil drain hose originates. It got stuffed inside transom and now I know to look dead center at sump bottom of pan. Was trying to find on sides of sump like automotive before I saw ur vid. Thank you.
@@moccasinmarine dang, I’m in Idaho. How many do you usually build in a year? And do you sell them nationwide or just locally? Thanks for the videos they are very helpful.
@@eddygoodwin7089 I try and maintain 1 build a month but that slips when the scope creeps to restoring an entire boat. I sell engines to a mechanic on the gulf coast too. I could mount an engine on a pallet and ship anywhere if needed. What size engine do you have?
Forgive my naivety if that is the case...but if the boat has an alarm that will sound already, is the swap needed? You mentioned that this would sound the horn, so that threw me a bit.
The Thunderbolt V module uses a temperature sensor which can’t be used as a switch to turn on the alarm horn. When the Thunderbolt module is removed (which is the point of the video series) you lose the alarm horn functionality because the sensor can’t switch the horn on and off. I include a new temperature switch to replace the sensor. My switch will turn on the alarm horn at 185 degrees F.
I've had the same issue with a friends boat, low voltage at the coil. I disconnected the stock hot wire to the coil and ran a jumper direct to the coil off the battery,... started instantly ! I measured voltage at the coil both static and running and shows only between 9.6 v and 7.5v while revving up with the stock hot lead hooked up. I suspect bad connections and corrosion so I'm gonna clean all the terminals from the ignition on back. The coil should see a steady 12 V all the time.
I have a mercruiser 5.7 fresh long block it’s a 355 with a slight marine cam from summit do I need to tune that cam to the ecu I can’t get this thing to leave the dock!!!
As a former machine shop manager and 40 years in the automotive industry, as per Felpro,Victor and other OEM gasket makers, the rule of thumb is NEVER,EVER put silicone on a gasket. PERIOD. On the ends. Yes, as there's no gasket there. Silicone acts like a lubricant, and the water/antifreeze will blow past the sealing surfaces. The raised plastic o-ring encapsulated gasket will crush to the head and intake. So many times we have seen intake gasket and water pump and thermostat gaskets slavered in RTV, with the passages clogged up and you could see where the w water blew by. The reason on 4.3 rear head gasket water ports failures, is there is no water passage crossover, and any contamination of the antifreeze will just stagnate and usually eat the mating surfaces of the intake. Usually when I build a mild engine, I drill and tap the manifold for a stainless steel or A/N style lines to help with cooling and heating of the heads. Please don't perpetuate the AutoZone myth and cause others to make a similar mistake. Even today, I can go to a repair shop and see mechanics putting RTV on every mated surface, using it to double up the sealing surfaces.
I’ve also been building engines for 40 years and I’ve never had a gasket failure with this method. I don’t know if you watched the video but I also don’t lather it up. I typically only put a thin film on the metal surfaces and I also only use the gray silicone in most applications. I’ve found the gray to be more durable. Also when I’ve had to pull parts back apart after the silicone has cured it’s anything but a lubricant. It has to be shaved off the metal surface with a razor the adhesion is so good. One other reason I do this. These are boat engines. Most are open cooling with no antifreeze to limit corrosion. The wider the gasket and the more metal covered by silicone, within limits, the less corrosion. The corrosion I’ve seen with boat engines is due to the lack of silicone. So I appreciate your input but I will continue to use my proven methods.
@@moccasinmarine again, I get where you are coming from, as there's always exceptions to each rule. I sold ac Delco reman engines in the 90's, just like the overheat freeze plug for warranty purposes, Delco would not warranty a engine with excessive rtv on gasket surfaces. I watched your videos and from others. I lived in Virginia near Virginia Beach, we built all the Mercury marines and OMC as well as others. Our problems were the brackish water we used our engines on. We had the crab fisherman further up the Chesapeake bay and near the Suffolk side, which were all brackish. Every year, engines were being rebuilt because of the internal rusting. Of course we had the ocean side, but those were normally big blocks, or huge diesel engines. Coming here to Michigan, the great lakes are not as hard on a marine environment. You have your proven method and I went with what the factory warranty preparation required us to do. Thank you for replying back to my post. I enjoy banter with all different points of view.
@@TheBobdesigns4262 if you watch enough of my videos you’ll see that I’m open to improvements all the time. I constantly try and save time on my processes. Not putting silicone on gasket surfaces may just be one of those tasks I could save time on. I’ll look into this further. Thanks for the input again.
Did you ever figure out how to scan the computer I have a 5.7 mpi I can’t get to plain out once in the water brand new motor not sure what’s goin on I need help!!!!
The MEFI computers have a safe mode that limits power. You’ll need to see if there are codes stored in the computer. It can be done without a scanner. I haven’t done a video of it yet but I plan to soon.
Hi, again.Well I went to do my valve adjustment My mercruser 3.0 does not have the harmonic balance notch or the tdc indicator numbers? What gives? I have a 2003 4 winns freedom 180
If you are missing the timing pointer and the TDC notch on the balancer then you may need to get a professional to complete the work for you. You’ll need the timing marks for several tasks and it takes a very knowledgeable mechanic to work around the loss of the timing marks.
@@chrisjones3038 the questions and statements you are asking tell me that you don’t have the knowledge to do this yourself without significant help. I can’t give you one on one help. All the information is in my videos but you’ll have to figure out what to do. To set the timing with a timing light once the engine is running you’ll need very precise timing marks. It’s a complicated process to re-establish the timing marks once they are removed. Why are the timing marks not there is the first question to solve.
No the bellows is held in place by a metal band that is pressed into the inside diameter of the bellows. As hard as they are to get out I’m guessing they must work well.
You found it. This video introduces the kits. There are 4 kits, 4.3 TB IV, 4.3 TB V, 5.0,5.7,6.2,7.4 TB IV, and 5.0,5.7,6.2,7.4 TB V. Email me at moccasin.marine.llc@gmail.com, include your engine serial number, your shipping address, name and phone number and I’ll send you a quote/ invoice via SQUARE. You can pay the invoice to purchase or decline to go another route. The invoice will include the kit contents, and total price including shipping.
Hey, man, I have a unrelated question. I also have a mercruiser 3.0, do you think it's okay to add some oil additive to clean? Such as slick 50 or the other stuff in the yellow bottle can't think of the name right now.😅
I would not add any additives other than a bottle of ZDDP at each oil change. The 3.0 engine is a flat tappet cam engine and modern oils do not provide good lubrication for flat tappet cams. ZDDP used to be in oils but was taken out so you need to add it back in at each oil change.
I got one more question.I am adjusting the valves thanks to your video Can I find the gasket at a autozone Or can I use just straight gasket maker really carefully? Can't seem to find a valve cover Gasket with five Boat holes. Everything I find on line will take weeks to come in
The IAC is from a ford! It doesn't have a cam sensor. Instead the distributor's sensor is used for cam position, which is not a standard distributor reluctor. So thats how it sequences the multiport injectors correctly. As you mentioned, the spark is generated off the crankshaft sensor. This eliminates the timing issues from torsional twist in the cam (actually a significant thing in performance engines), along with backlash from the timing chain and distributor gear. I'm tearing down a 2006 5.7 MAG MPI right now. Mine doesn't have the fixed distribuor clamp - mines adjustable. Mine was never significantly worked on previously. Unfortunately i have a scored cylinder 6. One notable difference is my cool fuel system is under the alternator, and has 2 fuel pumps
@moccasinmarine Yep! It's from a Ford Winstar (and probably a bunch of others). Careful using non OEM parts for the IAC - some work well, while others don't, or fail quickly... The GM IAC's I've seen in the past were 4 pin stepper motors (ie 2 internal coils), with a little pintle that moved in and out from an internal motor driven screw. Apperntly, Motorola made the ECM's for Mercruiser. The rumor I heard for using a Ford part was there was only one I/O left in the ECU. The Ford part requires only a varying voltage(probably via PWM) and a ground/power source. It works much the same way an audio speaker works. The 350 MAG MPI is based off GM's 1996-1999 Vortec 5700. Unfortunately, a lot of parts have been changed out/modified when converted to marine.
Hello Moccasin Marine, at 3;03 of the video your pointing out the broken oil pressure switch what is the hole just above that? thanks for all the great info Take care
As proof that these engines are car and truck engines at heart, that hole is for mounting an automatic transmission shifter linkage back when the shifter was mechanical on the steering column. It’s not used on any boats.
How dose the bottom bearing shell go is the square hole same way or opposite as I got an engine and they are all over the place one way and other opposite way 🤔
The tangs on the bearings go on the same side. There is a video somewhere on my channel showing this. If your engine has them all over the place that builder really screwed up bad. The bearing caps are machined with the rods together. Flipping them around will destroy the bearings quick. Watch this video at the 3:50 mark. It shows the bearings and caps going in. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-vGJtCt5Epns.htmlsi=3i80uCRSAKI8kUeM
You use what ever size pistons that fits the bore up to 0.060” oversize. They generally don’t make pistons larger than 0.060” larger so that’s as large as you can go. The machine shop decides what oversize bore to machine it to based on what it takes to repair the bore damage. They can look at a damaged bore and know it might take 030 or 040 to clean up.
@@moccasinmarine didn't know that. I "assumed" Volvo pistons were different from the one's that came with the 4.3 truck engine I'm using. I'm still learning and putting together a 4.3gl engine now. I spun a bearing in the last engine when I made a sharp turn on the lake
@@jsolo7576 go back and watch the video again but pay attention to the piston discussion. I use 1995 and earlier pistons on all engines because they are cheaper. Same piston just slightly bigger rings than 1996 and later. Saves about $50 per engine. Adding to the above if the block requires a larger piston than 060 the shop can sleeve the bore to save it at $100 per bore. After 2 sleeves it can be cheaper to find another block
I had to rebuild my 1995 bowtie in 2008 after running some low octane fuel on Lake Superior where they only had 87 octane and blew the lands off the pistons. I had the timing advanced quite a bit to run 93 octane on my home lake and didn't retard it before the trip (big mistake). The cylinders were just fine and no ridge, so only had to re-hone the cylinders at standard bore. When I rebuilt it, I did use Vortec heads, a CS XM 262H-12 cam, and a Performer Air Gap Vortec intake. I kept the same 9.4/1 compression ratio but did use hypereutectic replacements. One extra thing I did was to enlarge the wrist pin clearance to ensure it wouldn't seize from any sudden temperature change. This was recommended to me by a couple of engine builders in the Minneapolis area. Dyno was 353/397 with a Holley 600 and extra spacer plate. It's still running strong after 16 years.
Yes I pretty much stay in business due to people running 87 octane Ethanol gas. The combination of low octane and running 3-4% leaner due to Ethanol destroys engines.
