AQ271C ignition troubles.

[Scott Danforth]

background: 1988 AQ271C. last year had errant backfiring, multiple cylinder firing issues. noticed tracing in the cap, replaced it, all was good for a while. Engine would run, however only at idle, and without much load. about 20 hours later, same thing. cleaned cap - back up and running. end of season, problem cam around again. cleaned cap, back up and running.

when the engine was apart this spring, I cleaned the mechanical advance linkages, and lightly lubricated. I verified that the timing mark on the damper did correspond with TDC marks on the timing gears, so the outer ring has not changed.

today: new cap, rotor, plugs..... first time on water since upgrading cam and heads. engine idles fine, runs fine on muffs, however put a load on it and it falls on its face - backfiring, misfiring, etc.

timing is dead on at 8 degrees BDTC at idle. about 20 degrees BDTC at 2000 rpm about 28 degrees BDTC at 3000 rpm (checked on muffs)

I have replaced cap and rotor (Sierra) and plugs (NGK).
I have not yet replaced wires, however plan on that shortly.

I suspect the distributor over the coil, mainly due to the frequent carbon tracing.

anyone have any thoughts?

 

[Don S]

Re: AQ271C ignition troubles.

If you sprayed a lot of lube of some kind on the distributor weights & springs, it can cause the tracking.

 

[Scott Danforth]

Re: AQ271C ignition troubles.

I did not spray lube, I used a bit of white lithium grease applied with a q-tip. I will take a look to see if that is the cause.

 

[Maclin]

Re: AQ271C ignition troubles.

Scott,

Are you getting the cap from Volvo? The one with the ridges inside around each plug contact and around the coil contact? Some caps are all flat with no ridges, the ridges help to thwart the tracking. You may know all of this, if so I apologize, I tend to post for a wider audience.

I ordered a cap from a parts counter that could get Volvo parts. They had a lot of VP stuff in stock usually but had just ran out of the cap, and the parts guy said Hey the OMC and Merc cap is the same so he brought one out. It did not have the ridges and also had the aluminum contacts so I declined and waited for the VP one to come in, and it had the ridges and more coppery looking contacts. Got the VP rotor also. These have been in since 2007 and running perfect

I always bought the more expensive thicker caps back in my hotrod days also, I believe in the ridges and non-aluminum contacts.

 

[Scott Danforth]

Re: AQ271C ignition troubles.

I had a mallory cap on it, and now have a sierra cap. both have brass contacts, no ridges. the tracking is on the inside of the cap

 

[Maclin]

Re: AQ271C ignition troubles.

The ridges are on the inside, to make the path harder for any arc to track along the inside of the cap.

 

[Scott Danforth]

Re: AQ271C ignition troubles.

replaced coil and wires. when replacing the wires, about 3cc's of oil cam out of the wire/coil.

boat idle was 250 RPM higher and much smoother. will drop it in the water tomorrow or wednesday for the litmus test. thinking the bum coil was

 

[Scott Danforth]

Re: AQ271C ignition troubles.

dropped boat in the water, engine is strong right up to the ignition breakup about 4400 rpm. guessing a new distributor is next.

anyone have a suggestion Mallory vs Pertronix?

 

[Maclin]

Re: AQ271C ignition troubles.

Scott,

Do you still have all OEM wiring hooked up? Just wondering if #22 in this pic is there and at play....

 

[Scott Danforth]

Re: AQ271C ignition troubles.

no, the speed limiter is in a box in the garage.

 

[Don S]

Re: AQ271C ignition troubles.

anyone have a suggestion Mallory vs Pertronix?

Delco EST. Only way to go. All electronic. In common use and lots of documentation from Volvo.

http://www.michiganmotorz.com/delco-voyager-marine-electronic-distributor-p-121.html

 

[Scott Danforth]

Re: AQ271C ignition troubles.

pulled the distributor apart again, and cleaned and re-lubed. put the boat back in the water yesterday. Same issue. motor runs like a scalded cat right up to about 4300/4400 on the tach and thats it.

thought of going with the EST, however I want to be able to control my destiny so to speak. I have had nothing but problems with delco distributors in the past 10 years so I will be avoiding it.

thinking of going with the pertronix unit. the malory is more money, and the advance curve kit is separate. Pertronix advance kit comes in the box. Both offer 24 degrees of advance out of the box. both are adjustable as far as ramp rates and total advance.

this will wait until I have spare boat cash. I just totaled up what I dumped into the boat so far this year..... never do that

 

[PiratePast40]

Re: AQ271C ignition troubles.

I hear ya man!

 

[Scott Danforth]

Re: AQ271C ignition troubles.

update. got really tired of dealing with the old distributor and the problems, especially after being stranded by it.

so, a few weeks back, ordered the Mallory unit. installed it last night. motor fired right up immediately - not the usual crank for 5 seconds. got it to approx idle, then started setting the timing.

after setting the timing, the idle was perfect. a few quick blips of the throttle and it instantly snapped to high RPM.

next - headed to the water. supposed to rain this weekend, will see.

kind of curious as to exactly how bad the spark profile was with the old unit.