Logo
FULL SITE MENU

AQ170 misses at high end

S

suds

Member
"I have twin AQ170's in my

"I have twin AQ170's in my boat. One runs great, the other misses at around 3000 rpm, idles fine. New fuel pump, ignition parts, fuel filter and compression is good. Runs cool, same gas supply as other motor. Clean carbs, did not rebuild. Replaced fuel lines. Any answers?"
 
"Could it be something related

"Could it be something related to your Pertronix kit (adjustment, etc)? Maybe swapping distributors will give you the answer."
 
"I will give it a try, there&#

"I will give it a try, there's not much adjustment, only gap, timing is good and I just had both distributors sent out to be adjusted, they're right on."
 
"I know the Pertronix kits are

"I know the Pertronix kits are very reliable, but swapping distributors can be done quickly and that will clear any doubt. I have also advised other forum members with similar problems to temporarily hotwire the + of the coil with the + of the battery to discard any potential wiring problems.

It could also be one of your carbs flooding when the fuel pressure increases with the higher RPM, or one of your carbs butterflies getting stuck at half trottle. I presume you have synchronized your carbs and the linkages are free and well lubricated."
 
"I have sync'd the carbs,

"I have sync'd the carbs, only at idle. Do you sync them above idle?
This did occur to me that a butterfly could be loose. The pertronix guy also told me to run a lead in the same manner, I forgot. All linkages are free and lubricated."
 
"Thanks by the way. I read som

"Thanks by the way. I read some other answers to some of the questions. In regards to the uni-sync. If you cut a 1 1/2" to 2" piece of 2" fuel line, this sits right over the center of the down draft and the uni-sync sits above that. Smaller to place on your boat if you keep it on the boat, and easy to handle. Thanks again, I will do some troubleshooting on my boat and be back."
 
"Ken, what I have seen in the

"Ken, what I have seen in the past is the butterfly spindle jamming in the aft carb, possibly because it is more likely to be exposed to water. Perhaps it would be a good idea to remove the flame arrestors and make sure that both butterflies are opening at the same time and that none of them is getting stuck.

Regarding the Uni-sync tool, I have always set the carbs at idle, then try again at say 1500 or 2000 RPM, just to make sure that the reading is still identical in both carbs."
 
"Ran to Catalina Thursday morn

"Ran to Catalina Thursday morning, ran fine. Ran out a couple of miles, trolled around all day Saturday, caught lots of fish, went to run back and seemed like I had fouled a plug or two. Rev'd it up to get it back, thought I did and moored it. Left Sunday, again it did not have the power of the port motor, and did not get much past 3000rpm. About 5 miles from home it came alive, all the power it should have, even better than Thursday. Slowed to take a picture and it did not come back to the power it had. Strange."
 
"First, at least you had a goo

"First, at least you had a good fishing day. That's a bonus.
biggrin.gif


Did you rebuild the carbs? Just to discard the possibility of one of them flooding because of a defective needle valve.

The other thing you can do, as I suggested above, is to hotwire the + of the ignition coil to the battery when you have no power in one engine. If it clears the problem, then you know it could be the ignition switch or the kill switch and associated wiring giving you trouble. If the problem persists, it may be one of the carbs that's flooding."
 
I kind of agree with you on th

I kind of agree with you on the carbs. I did do a jumper wire to the coil did not change. I am going to pull the plugs and see if they tell me which carb might be bad or rebuild all three. Just seems odd the way it kicked in all of a sudden an ran like it was supposed to. I still need to swap out port for starboard to see if maybe the Pertronix module is bad.
 
"El Pescador, let me run this

"El Pescador, let me run this by you. My alternator was not charging I noticed when I was heading to the island. The next morning I cleaned all of the terminals and put them back on with some grease to keep out corrosion. Started the motor and the alternator was charging. Heading home it was not charging and the motor wasn't running up to snuff, but I did not look at the amp meter when the motor kicked in. Could I have a bad ground. I am going to check it all out this afternoon, have not had time to get on the boat this week yet. Just a thought."
 
"Yes, you could have a bad gro

"Yes, you could have a bad ground, probably between the engine block and the batteries. That would explain why you have so many electrical problems with that particular engine and not with the other one. Definitely worth checking."
 
"for anyone that might be inte

"for anyone that might be interested, i had nothing but trouble with the triple solexs on my aq170c, i have now solved the problem. i took the pieces of crap off, i made a manifold adaptor to fit across to fit across the volvo manifold out of 75x38 mm box section and fitted a ww stromberg 2 barrel off a 302 cleveland ford. now i have more power, no flat spots or hesitation and perfect idle all the time, i have not got any economy figures yet but it should be about the same. this is the biggest improvement i have ever had with an engine."
 
Back
Top