Volvo Penta 230B backfire through Carb

[Doug-ole-waterdog]

Hello, I this is my first thread. Been reading, but none of the articles answered my issue.

I had the boat at the lake a week ago and it ran pretty good for about 45 min. 30-32 MPH. That was when I had the 0* BTDC and 38* dwell. It ran a bit warm 200* I slowed down like to pick up a skier and let it idle for a few min. Then shut it off for about 5 min. Started it up and all the problems came back.

I have new battery, fuel pump, distributor cap, points, condensor & plugs. I have cleaned solex carb on engine. Junk on screen in accel pump and in all jets. Cleaned out passages and Accel pump. I have ran w/muffs on two gallon can to eliminate tank. No difference. Tank is plastic. Blew through vent hose and pushed gas out of tank. Sucked through pick up hose and got all fuel. Disconnected fuel pump line at carb and plenty of fuel going to carb. Accel pump steam through candy cane is strong. Disconnected linkage and opperated throttle by hand and watched fuel in barrel looked good fuel coming out of center post at all holes. Nothing comes out of the tube from the bowl, but tube is clear.

Engine will only start @6*BTDC if dwell is at 35-42*. If I set dwell at 62-63 engine will not start unless 0*BTDC or less. I can start engine on either setting on muffs and can idle up RPMS slowly. If I try a rapid accel I get a backfire with flames out of the carb.

I had the engine running with no back fire @ -2*BTDC (hard to see behind pulley) and dwell at 38* took it to lake and under load pops and no power.

I keep cleaning carb each time and trying to set Dwell @62-63 and 6*BTDC like it says on the engine and on other threads and I can't get there.

Any help is appreciated Doug

 

[jtybt]

Re: Volvo Penta 230B backfire through Carb

If it ain't the accelerator pump, you probably have plug wires crossed or loose.


Sorry, I don't know volvo. What engine is that?

What work have you done on it recently? have you pulled the dist?

 

[captmello]

Re: Volvo Penta 230B backfire through Carb

You may want to check the timing belt.

 

[Doug-ole-waterdog]

Re: Volvo Penta 230B backfire through Carb

Thanks! Plug wires have been traced and in proper holes. Ran continuity test on plug wires, all good and snapped in place. Timing belt looks good all groves in place and tight.

The Distributor is all the way to the left, counter clock, no adjustment left. When I open points Dwell goes down when I close points the Dwell number goes up.

What comes first *BTDC or Dwell? Chicken and egg thing. Been told different opinions.

How do you set the Accel pump? I thought I set it back where it was but might be wrong.

This is a Vovlo Penta 230B the only ID I can find is on the valve cover

230BUS
2200026774
863534 ?not sure on last sequince

 

[Maclin]

Re: Volvo Penta 230B backfire through Carb

You have to get the dwell correct first then set the timing. Changing dwell affects the timing, anytime dwell is adjusted you have to check/adjust the timing again.

Dwell can be measured in degrees or percent and the numbers are not the same, are you mixing those numbers up?

 

[captmello]

Re: Volvo Penta 230B backfire through Carb

The Distributor is all the way to the left, counter clock, no adjustment left. When I open points Dwell goes down when I close points the Dwell number goes up.

I'm pretty sure the distributor can be repositioned for adjustment.

 

[Doug-ole-waterdog]

Re: Volvo Penta 230B backfire through Carb

Thanks! I use Actron meter. I hook the red lead to the -post on the coil and the black to a ground. I set it on Dwell setting on 4 cyl. I have to take the cap off each time I change the setting. I set about .016 to start with feeler. Then turn the engine over and watch the meter. I get it about 62-63 on the meter (with out running) after a very small agustment, usually closer together. Then I try to start the engine.

If I turn the distributor all the way to the left (counter clock) the engine tries to start, but rough and acts like it is running on two or three cyl. Then dies.

I have set the Idle jet at about 5 turns out (that is the only adjustment I could find it is located between the valve cover and carb body toward bottom). That is where it was when I started cleaning carb.

I did take the distributor out to check the advance parts when I replaced the points,they all move and springs are in place, but I thought I got the dist. back in the right tooth.

I just removed the syphon valve and cleaned it. It did not appear to be clogged. I blew throught the pick up line and could hear bubbling. I cannot remove the "solid pickup line" this is a poly tank and only acces is through float hole.

I will go reset as suggested and report back.

 

[Doug-ole-waterdog]

Re: Volvo Penta 230B backfire through Carb

I'm back. Set dwell to 62.6 and had to turn dist all the way left (Counter)to stop. Engine starts and timing says -1-2*BTDC. when I try to accelerate engine pops through carb and trys to die. Pull back to idle and fine at 875-900 rpm.

If I remove the distribtor again and roate the shaft. which way do I go? Can I tear anything up? My thought is to turn shaft to right one tooth? If I do that would I start with dist at the other end of adjustment and turn to left to get back BTDC?

 

[captmello]

Re: Volvo Penta 230B backfire through Carb

I think your on the right track. If you can get the timing mark on TDC, needs to be on the compression stroke, or you're 180 deg off and won't start at all, the rotor should be pointing toward or just before #1 spark plug on dist. cap.
You can turn the distributor anyway you want as long as rotor is pointing toward #1 spark plug.

That should get it close enough to run. Once is running, you can turn the dist. by hand to time it by ear, now check the dwell, get it set, then check the timing with the light.

Let us know what happens.

 

[Doug-ole-waterdog]

Re: Volvo Penta 230B backfire through Carb getting closer

Re: Volvo Penta 230B backfire through Carb getting closer

OK call me inpatient, but I thought why not take the dist bolt out and turn dist a bit more to left. I did, the mounting hole is about half covered. I have the dwell at 61 and the timing at 6-7* BTDC. The engine starts well, runs a bit rough. I can accellerate without pop unless I hit it pretty fast.

Now when I take the dist out do I hold the rotor in the same place and rotate the dist case so I can put the bolt back in?

Then do I set Dwell again and time again?

I have the idle jet 6 turns out. Will this contribute to the pop? Is there a rich or lean jet on this Solex?

 

[captmello]

Re: Volvo Penta 230B backfire through Carb

The book says to back out the idle mixture screw 9 1/2 to start.

you rotate the whole thing rotor and dist.

 

[Doug-ole-waterdog]

Re: Volvo Penta 230B backfire through Carb

Thanks for all the help! I took all the plugs out and put long screw driver in #1 cyl. rotated the crank until timing mark came to 0. The #1 cyl was at TDC. I took the distributor out and rotated everything to the right. when I put dist back in the rotor was pointing at cyl #1. set the points to .013 and it started right up. I shut it off and set the dwell to 61.8 ( as close as I could get it kept going back and forth settled for 61.8). I then put timing light on and set to 5-6*BTDC. runs good. only pop is if you hammer the the throttel. Even then it seems to stall a bit then pick up. The carb idle jet is at 6 & 1/2 I will move it to 9 on the water to see what happens. I think I am ready to go to water. I don't know if I will get to go today or not, but will let you know the the outcome.

Thanks Doug

 

[Robj]

Re: Volvo Penta 230B backfire through Carb

If it is still not running right, I would check the timing belt. It may have jumped a tooth or two.

Have a great day

Rob.

 

[Doug-ole-waterdog]

Re: Volvo Penta 230B backfire through Carb

Thanks to all who joined in on this project. I will go to lake Mon. morn and try. I feel real good about this we are at all fact spects and it sounds good. The suggestion regarding the cyl #1 at TDC timing mark on crank and the rotor pointed to #1 on cap worked like a champ. All the other parts and problems would have occured on the lake if I had not have followed your suggestion. I will report the out come tommorow.

Special thanks to all involved. I will cruse this site and see if I can help others. Try to give back!!

Doug

 

[robjen1019]

Re: Volvo Penta 230B backfire through Carb

My aq151 was backfiring really bad before I changed my timing belt. New timing belt and problem was gone.

 

[BLDFW]

Re: Volvo Penta 230B backfire through Carb

I then put timing light on and set to 5-6*BTDC. runs good. only pop is if you hammer the the throttel. Even then it seems to stall a bit then pick up.

That still sounds like an accelerator pump problem. I experienced this myself. Under hard throttle it was going lean because the pump plunger was malfunctioning in it's sleeve and not giving enough gas at that moment. It would backfire and lag to the point of stalling for a second and then the RPM's would come back as it got more gas via the normal flow. I rebuilt the carb and it performs 100% better. I'm still tweaking it and have to double check my timing but it's running a lot better than before.

 

[Doug-ole-waterdog]

Re: Volvo Penta 230B backfire through Carb

Thanks for the suggestion. We ran on the lake this morn. I even pulled a skier, but the carb acts just like the last entry. Idle up start to pull and stalls for second like running out of gas (1-2) pops and then rpm's increase and away we go. Skier will drink a lot of water before plane out. Don't think I could pul a slolum. Running a bit hot for me ( guage reads 200* laiser temp on head shows 192*, after running 3600 rpm's for ten minutes. Cools right down at idle to about 180*. Fresh water pump lines run about 95*. We ran for about 45 minutes (1/4) tank of fuel. Running28mph @3800RPM. Did not try to run faster worried about temp.

Adujusted idle jet no effect on stall. Adjusted pump linkage to a bit longer throw and that seemed to help. I think it is running out of gas until vacume in the barrell picks up and gets down draft increased.

Your thought please.

Doug

 

[captmello]

Re: Volvo Penta 230B backfire through Carb

Hard to say....

the temp sounds very close to normal. If you can, next time out check the temp right at the temp sensor with the laser, unless that was the 192.

Did you ever run at WOT? I'm wondering how it may have performed. You should be getting close to 5000rpm. Will the engine run up to that speed?

If you increase the throttle slower will it accelerate smoothly?

 

[Doug-ole-waterdog]

Re: Volvo Penta 230B backfire through Carb

That temp was on the head under the valve cover. This was the hotest point I could find. I checked to the left of the heat exchanger at the hose barb. That was 170*. No I did not WOT, I was worried about the temp and wanted to run through the gas I have treated it with Sea Foam. I believe it would get to the red line with no problem. If we are traveling at 25 mph ( 3800r's) and I throttle up it has quick response. Yes if I accelerate very slowly past mid throttle it will climb very fast. I can push through the stall if I am patient when it begins to stall wait a second then push throttle slowly it will rev quickly. I thought about extending the adjustment on the accel pump to have a longer throw for the pump, maybe dumping into barrel longer to get past the stall. I can't tell if I am getting to much gas (flooding) or starving until down draft takes over.

 

[captmello]

Re: Volvo Penta 230B backfire through Carb

It looks like you have an external accelerator pump on your carb. Is it this one?

http://www.volvopentastore.com/CARBURETOR/dm/*******.545848829--**********.539533045--store_id.366--view_id.320870

Rebuild kit on another site almost $200. Comes with new diaphragm.

Did you pump the throttle when stopped and looked for gas to spray out?

I'd still want to run it at WOT to see if it really goes or not. has to be on the water under load of course, you can't guess. However it sounds like it runs good with the one exception.

I wouldn't keep screwing with carb linkage. If you believe all else is good, rebuild the carb, or at least try to track down the accelerator pump diaphragm. Its easy to swap that out.