I chatted with tech support [SWPERFORMANCEPARTS] and they seemed sympathetic, but my guess is they possibly got a mismatched set of modules from their supplier, MOBILETRON. Mobiletron appears to make good stuff, and I may be mistaken, but according to page 157 of their catalog D1965 is the marine one. D1980 is the auto one. The distributor I received had a D1980 installed. The full text stamp was: “Mobiletron IG-D1980C M0819 T9025778-C 2775”This is great insight, thank you! The ignition coil I bought is the specific Volvo part # - the distributor I ordered is this one from A-Team, should I cancel that and send it back?
Which distributor did you go with that worked for you?
A-Team Performance - EST Marine Electronic Ignition Distributor EFI - Compatible with Mercruiser Chevy Volvo Penta OMC Indmar 18-5513, 18-5476, 807964A1 V6 4.3L Red Cap
Ok, no anti siphon- the engines and fuel system are about 2.5 feet above the tank. It’s just hose from the an elbow at the tank to the fuel filter, then pump and short braided line. Glad yours is running good!!If the fuel line dips below the level of the tank, an antisiphon is required.
On my boat this was a problem, the engine would start and rev in neutral just fine but would not plane out the boat. I went through the ignition and carb, nothing really amiss, took it to a good marine mechanic and that's what it was. The boat builders sometimes use a cheap one that corrodes, he put in a better quality one and it's been fine since 2004!
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Ok, this is great, thanks! I’ll verify tomorrow am. The distributor cap wouldn’t screw down on one side- I suspect this is part of the issue.I chatted with tech support [SWPERFORMANCEPARTS] and they seemed sympathetic, but my guess is they possibly got a mismatched set of modules from their supplier, MOBILETRON. Mobiletron appears to make good stuff, and I may be mistaken, but according to page 157 of their catalog D1965 is the marine one. D1980 is the auto one. The distributor I received had a D1980 installed. The full text stamp was: “Mobiletron IG-D1980C M0819 T9025778-C 2775”
It may not be the D1980 prefix, but perhaps the M0819 suffix. It would not go into base mode, and the timing curve was all wrong. I pulled it right out to return.
I ended up getting an AC Delco stamped distributor [part number 1103782], not sure what module will come on it. I also ordered a standalone A-Team [Mobiletron] module, hoping to get the D1965, or perhaps the “M1017” suffix. Finally, as a backup I got the the industrial engine version of the module from Hyster (forklift): “HYSTER IGNITION IGNITER MODULE 1460387” which has “GM 399 4L01” stamped on it - best I can tell, the “399” being some sort of ACDELCO/GM speak for the marine version - again as a backup.
Link to Mobiletron’s catalog p.157 explaining above:
https://www.mobiletron.com/Content/document/200521-車王-Ignition/mobile/index.html#p=157
Link to standalone module:
A-Team Performance Ignition Module Compatible with GM Mercruiser 3.0L 4 Cyl, 4.3L V-6, 5.3L 5.7L V-8 Engines with Delco EST Ignitions 18-5107-1 — Southwest Performance Parts (swperformanceparts.com)
(again, I am not certain that is the marine flavor of this module, all I can say is that the one I got in my distributor had the wrong module)
Standalone link to Mobiletron D1965: https://www.mobiletron.com/Product/detail/7486/IG-D1965
Good luck.
I love the 1966 tech! If it breaks down on me 12 miles offshore with the kids and wife I have a good chance at fixing whatever is wrong with simple tools and no computer needed. I’m not a Luddite, I have a 2023 M2 MacBook Pro, tech where it makes sense. Displacement where it doesn’tPS
I'd like to see what the spark plugs look like, good engine vs the one that is surging.
blistered white electrodes, fuel starvation...float too low....anti siphon clogged...
black electrodes, maybe choke not staying open float too high, grit in needle valve
one last thing I'm assuming electric fuel pumps, have you checked fuel pressure? Only 5-7 psi need for a carbed engine.
just properly adjust the choke. the holley carb hasnt changed much in 60 years. Just as easy to get working correctly as 6 year old me found out nearly 50 years agoGood call on the choke, it’s been problematic on my old carbs. I’m just going to disconnect it, we don’t need choke here in Florida but maybe 1 day a year.
get the test fitting. https://www.cpperformance.com/p-62962-fuel-pressure-tee-91-806901.aspxEdit- what is the procedure for checking fuel pressure? They are electric pumps.
If you think the fuel lines look bad from the outside I would replace them could be degraded on inside?Update- Thanks again for all the ideas here folks. I swapped the carburetors from engine to engine and did a sea trial. Still only hitting 3500RPM. So, not the carbs.
No anti-siphon valve inline either- 2.5’ up from tank to fuel filter housing. Will be replacing those lines, they are worn.
Removed the choke wires and sea trialed again, no improvement.
The distributor cap however- right side cap screw hole is stripped out and will not stay down on distributor. There is also damage to the female plug on the module; I put the cap and rotor on from the new distributor and it was clicking away like a tap dancer when running, I held it down and there’s a bit of gap happening. It’s lifting up.
Tomorrow- new distributor install, verify TDC, RE-do compression check personally (sus initial data of 195 all except one at 175), time engine, new plugs (test each plug) as I go.
Anything else to check / verify?
Does it make sense that the motor would dip / drop / surge ~ 500RPM under load and not make initial wot RPM on trying to plane out acceleration if the distributor cap is jumping up from the rotor / distributor? Is that would would happen if that’s the cause?
Ok, no anti siphon- the engines and fuel system are about 2.5 feet above the tank.
Update:I chatted with tech support [SWPERFORMANCEPARTS] and they seemed sympathetic, but my guess is they possibly got a mismatched set of modules from their supplier, MOBILETRON. Mobiletron appears to make good stuff, and I may be mistaken, but according to page 157 of their catalog D1965 is the marine one. D1980 is the auto one. The distributor I received had a D1980 installed. The full text stamp was: “Mobiletron IG-D1980C M0819 T9025778-C 2775”
It may not be the D1980 prefix, but perhaps the M0819 suffix. It would not go into base mode, and the timing curve was all wrong. I pulled it right out to return.
I ended up getting an AC Delco stamped distributor [part number 1103782], not sure what module will come on it. I also ordered a standalone A-Team [Mobiletron] module, hoping to get the D1965, or perhaps the “M1017” suffix. Finally, as a backup I got the the industrial engine version of the module from Hyster (forklift): “HYSTER IGNITION IGNITER MODULE 1460387” which has “GM 399 4L01” stamped on it - best I can tell, the “399” being some sort of ACDELCO/GM speak for the marine version - again as a backup.
Link to Mobiletron’s catalog p.157 explaining above:
https://www.mobiletron.com/Content/document/200521-車王-Ignition/mobile/index.html#p=157
Link to standalone module:
A-Team Performance Ignition Module Compatible with GM Mercruiser 3.0L 4 Cyl, 4.3L V-6, 5.3L 5.7L V-8 Engines with Delco EST Ignitions 18-5107-1 — Southwest Performance Parts (swperformanceparts.com)
(again, I am not certain that is the marine flavor of this module, all I can say is that the one I got in my distributor had the wrong module)
Standalone link to Mobiletron D1965: https://www.mobiletron.com/Product/detail/7486/IG-D1965
Good luck.