voltage & rough idle

[mattlamb]

Hi all my voltage is going as high as 17volts(as high as meter goes..) and up and down a lot… I also have engine rough idle.(fixed everything else, I even varnished the woodwork)

Think it's the alternator?

I need a voltage regulator for a Motorola 37 amp alternator?

Mine says its an R7-1 regulator

any idea if I can still buy these?

Thanks

Matt

[Al Schober]

17 volts is too high. You're going to fry your batteries.
Sounds like a regulator issue, alternator seems to be doing it's thing.
You can replace the original regulator, but why? It didn't do a good job before it died. That regulator was designed for automotive use with a lower charge voltage than you want for a marine recharge application.
As a minimum, I'd recommend a different regulator - something designed to put 14-14.5 volts to the battery. This would get you back in business. Later on (when you decide you want more amps) you can upgrade the alternator and still use the new regulator.
It's been a while since I've been shopping for this stuff, but there may be single wire alternators available today with both increased output current (60 amps seems to be a sweet point) and internal regulators designed for marine use (14-14.5 volt output). Be sure to get one with the spark suppression screens.
Rough idle? Have you cleaned out the idle jets in the carb?

[ndutton]

The coil could be damaged too.

[joe_db]

The coil could be damaged too.

No doubt - 17 volts

[joe_db]

17 volts is too high. You're going to fry your batteries.
Sounds like a regulator issue, alternator seems to be doing it's thing.
You can replace the original regulator, but why? It didn't do a good job before it died. That regulator was designed for automotive use with a lower charge voltage than you want for a marine recharge application.
As a minimum, I'd recommend a different regulator - something designed to put 14-14.5 volts to the battery. This would get you back in business. Later on (when you decide you want more amps) you can upgrade the alternator and still use the new regulator.
It's been a while since I've been shopping for this stuff, but there may be single wire alternators available today with both increased output current (60 amps seems to be a sweet point) and internal regulators designed for marine use (14-14.5 volt output). Be sure to get one with the spark suppression screens.
Rough idle? Have you cleaned out the idle jets in the carb?

The Motorola is very easy to adapt to an external regulator. Try one of these if you don't want to hunt down a 3 stage reg

https://www.amazon.com/World-Power-Systems-adjustable-regulator/dp/B00OBTZ8OE/ref=sr_1_1?dchild=1&keywords=transpo+regulator&qid=1587125142&sr=8-1

https://www.amazon.com/NEW-Adjustable-Voltage-Regulator-V1200/dp/B00OBTI5Q2/ref=sr_1_8?dchild=1&keywords=transpo+regulator&qid=1587125195&sr=8-8

Fancy 3 stage:

https://www.ebay.com/itm/Sterling-ProReg-BW-Advanced-Alternator-Regulator-100-Amp/173006488667?hash=item2847fd845b:g:K74AAOSwzrxUyWLR

[ronstory]

I've been a fan of this style alternator since all the regulator and trio bits are mounted on externally on the back of the alternator, which seems to run cooler. The Vset is 14.4V and output is rated at 55A, which means it can do 35A all day long... and 40A has been my typical max current on the A4 when the battery is low.

https://www.amazon.com/gp/product/B00KGIBD5W/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Just noticed that there now is a 105A version.

https://www.amazon.com/gp/product/B01LMD1Q2O/ref=ox_sc_act_title_1?smid=A3I4NLEIJJQG7M&psc=1

I have not done the external regulator conversion yet, but this is an unusual alternator case that I can't reference. The front and stator look like a straight Delco CS121, but the back of the case is unique with all the stator, ground and trio diode connections on back. If anyone has seen a standard case like that... please share.

If you head down that path, I have the wiring breakout diagram.

[mattlamb]

Part acquired

Local alternator specialist (Roberts in Victoria, BC - lots of old boats around here ) had the regulator in stock!

Fitted and volts are now stable, rough idle still an issue & no increase rpms in gear. (does increase when in neutral).

removed the throttle cable and the tried to adjust at carb, it feels like the throttle arm is slipping on the carb.

tiny hole in throttle arm lever.. not sure if its a old rusty allen screw?

any one ever remove one? might have to drill it out...