Forum: Cooling System
09-28-2022, 10:03 PM
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Replies: 5
Views: 1,043
MMI 502 pumps
The reason the shaft looks so different from the ones in our catalog is because the ball bearings are completely destroyed (probably from water leaking past the water seal for many years) and the...
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Forum: Cooling System
07-28-2021, 09:03 AM
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Replies: 3
Views: 1,790
Removing FWC belt
OM, The brackets of most front mounted FWC belt driven pumps are mounted under the top starter mounting bolt. After loosening that single mounting bolt, you can back out the belt tensioning bolt on...
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Forum: Overhaul
11-01-2020, 05:35 PM
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Replies: 123
Views: 29,362
Idler shaft puller
Hi Greg,
Hopefully you didn't tighten the inside part of the puller too tightly, in which case you should be able to wrap some protective material around the spindle and hold it gently with a pair...
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Forum: Reversing Gear
10-07-2020, 11:23 AM
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Replies: 3
Views: 1,486
Output coupling key
Mark,
I need to back peddle on one point I made in my previous post, which was that keys up to 1.5" are OK to use between output couplings and tail shafts. This is NOT the case. The tab on the...
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Forum: General Interest
09-27-2020, 11:28 AM
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Replies: 24
Views: 4,847
Coupling compatibility
Coupling compatibility depends on more than just the shaft diameter. The bolt patterns and facial features on the couplings are different between direct drive, V-drive, and reduction gear versions...
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Forum: Troubleshooting
09-18-2020, 06:19 PM
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Replies: 9
Views: 10,763
Valve spring material
Dave,
We questioned the manufacturer many years ago on this point, and they told us that it's normal for their stainless valve springs to have a bit of magnetic attraction. In all the years we've...
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Forum: General Interest
08-30-2020, 09:51 AM
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Replies: 27
Views: 8,656
Fuel supply
When you test the fuel pump, make sure you test it as it is being operated during normal service. For example, if you have an oil pressure safety switch as required by the Coast Guard and you're...
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Forum: General Interest
08-29-2020, 01:57 PM
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Replies: 27
Views: 8,656
Fuel supply
Splashlog,
Your most consistent current symptom, which has remained throughout your thread is that the engine starts and runs fairly well at idle but shuts down at higher power settings. I'm...
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Forum: Ignition System
05-12-2020, 12:28 PM
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Replies: 9
Views: 4,042
Ignitor timing
Surcouf; I can't follow your ohms checks completely, but the fact that your engine runs at all would seem to confirm that your Ignitor module is opening and closing properly. The fact that the...
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Forum: General Interest
01-10-2020, 10:18 AM
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Replies: 10
Views: 3,104
Ignition protection
Building on Neil's post, here's a link to one of our MMI newsletters in which we tried to explain ignition protection. The ignition protection reference comes near the end of the newsletter. Don
...
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Forum: Cooling System
12-26-2019, 12:28 PM
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Replies: 17
Views: 3,636
Thanks for the feedback
This is wonderful news! I suspect that it's too late to ask now, but did you happen to take any photos of the end of the relevant stud to show how its end looked? Studs usually have a very...
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Forum: General Interest
12-21-2019, 11:19 AM
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Replies: 13
Views: 4,090
Thank you!
John, just to add my personal thanks along with the rest of our MMI Team for your generous sharing of your experience over a large number of years. Your contributions have most helpful to a great...
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Forum: Overhaul
12-14-2019, 12:08 PM
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Replies: 152
Views: 58,536
Lock-n-stitch
Surcouf,
The threads on the plugs used in Lock-n-stitch repairs are tapered and shaped such that (as they are tightened) they pull the crack together. The shape of the threads was described to us...
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Forum: Cooling System
12-09-2019, 07:30 AM
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Replies: 17
Views: 3,636
Possible good news
nyvoyager,
In later late model engines we have seen quite a few cases where what you think is a piece of stud broken off in a manifold stud hole is really nothing more than calcified residue...
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Forum: Reversing Gear
03-11-2019, 06:44 PM
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Replies: 4
Views: 3,832
Shifting cable size
Rick,
The original Morse 6400 series shifting cables had 5/16" X 24 male threads on their end fittings. I'm afraid it won't be all that easy to find a clevis/turnbuckle with 5/16" female threads...
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Forum: Cooling System
09-26-2018, 09:32 AM
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Replies: 11
Views: 3,700
Suspending cores in castings
In the 1970s, foundries suspended the inner cores that formed water jackets on what looked like safety wire. Since these wires extended out through the mold, these specific areas were reinforced...
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Forum: Cooling System
09-25-2018, 04:52 AM
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Replies: 11
Views: 3,700
Leak in valve chamber
In each of the 3 or 4 cases that we've seen these leaks ourselves, Universal had drilled and tapped the flaws to 1/4" NPT pipe threads and then installed an Allen headed plain steel pipe plug. The...
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Forum: Ignition System
08-25-2018, 09:43 AM
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Replies: 5
Views: 2,394
Azazzera. Since you asked, here's a link to an...
Azazzera. Since you asked, here's a link to an online calculator that will help you determine the way resistance varies with temperature: http://www.endmemo.com/physics/resistt.php You basically...
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Forum: Introductions
08-10-2018, 05:35 AM
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Replies: 24
Views: 10,983
Coil wires
Terry, assuming that you have an Ignitor electronic ignition system, make sure it's the red wire from the distributor that connects to the positive of the coil and the black wire to the negative. Don
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Forum: Fuel System
06-20-2018, 11:23 AM
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Replies: 49
Views: 14,584
Oil consumption
We have very little history of unusually high oil consumption being reported. In case it helps your perspective, I can report that before I rebuilt it, the Atomic 4 in our first sailboat (our...
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Forum: Cooling System
06-02-2018, 10:03 AM
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Replies: 6
Views: 3,242
Water passageways in heads
Universal changed the coolant flow pattern somewhat over the years between the block and the head. They did this by eliminating certain holes in the head. Hole patterns in MMI heads reflect the...
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Forum: Cooling System
05-08-2018, 07:03 AM
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Replies: 56
Views: 27,486
Cooling system troubleshooting
There are almost too many really great troubleshooting suggestions in these recent posts to keep track of!! Thank you Cajun Spike, Tenders, sastanley, to name just a few. Don
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Forum: Exhaust System
09-03-2017, 05:18 PM
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Replies: 7
Views: 3,332
Exhaust leak
Hi Mary, I don't see where anyone has asked if the coolant level in your FWC system is going down in your expansion tank. Or, if you're using a colored antifreeze, does your leak look like that...
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Forum: Ignition System
06-28-2017, 12:50 PM
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Replies: 7
Views: 3,601
Ignition issue
Al, you're raising a very interesting question! You're correct in pointing out that both the primary and secondary windings of the coil share the negative terminal for their ground (through the...
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Forum: Troubleshooting
06-26-2017, 05:31 AM
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Replies: 27
Views: 7,119
Water in oil
I need to correct something I wrote many years ago. We used to think that the weep holes in Oberdorfer and MMI flange pumps were large enough to eliminate the possibility of water getting into the...
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