1997 200 OceanPro surging at idle

[dingbat]

The motor ran well all day while trolling @1200-1500 rpm. Dropped it out of gear to pull in the planer boards and it was surging at idle. Didn't look at the tach but I figure up and down maybe 100-300 rpm. Drop it back into gear and it idled like normal.

Ran 5 miles back to the marina @4500 rpm the and it purred like a kitten. Dropped it back out of gear to back into the slip and it started surging again although not quite as bad. I'm suppossed to fish all of next week so what a time for something like this to happen.

I running back down this morning to pull the plugs to take a look . Hopefully it's just a fouled plug but does anyone else have any ideas if its not the plugs?

 

[ezeke]

Re: 1997 200 OceanPro surging at idle

Start by looking for air intrusion anywhere along the fuel supply system.

You may also want to check your thermostats to be sure that the engine is running at the correct temperature..

 

[dingbat]

Re: 1997 200 OceanPro surging at idle

Thanks for the input

The plugs looked like they where running a little rich but not bad. I also checked the t-stats and looked around for a fuel leak but didn't find anything suspicious.

I changed out the plugs anyhow and figured I'd change out the filter element on the Racor while I was at it. It now seems to idle OK but I didn't get a chance to run it to make sure.

 

[HighTrim]

Re: 1997 200 OceanPro surging at idle

It does sound like there is an air leak on your fuel line, when it idles up like that it's running lean. Also check out the fuel primer bulb when it is surging. Ensure all fuel connectors are tight and secure. Could also be a fuel pump issue. Also when were the carbs last rebuilt.

 

[dingbat]

Re: 1997 200 OceanPro surging at idle

The first thing I checked was the primer bulb. The primer bulb was hard and pumping made no difference at all.

The motor had a complete go over last fall. The carbs where rebuilt and a new fuel pump was installed at the same time. I've had intermediate (three times this season) fuel restriction alarms which I?ve still not resolved.

I?m still fighting an intermediate fuel restriction alarm from time to time as well. I pulled everything from the elbow at the tank on back a few months ago and blew everything out. Everything was good until I got another alarm a week ago when I pushed the throttle up to WOT. I pulled the throttle down back under 5K rpm and the alarm went away. I guess the next step is to just replace the entire fuel assembly from the tank forward and see what happens.

 

[ezeke]

Re: 1997 200 OceanPro surging at idle

Did you replace the anti-siphon valve on your tank?

 

[dingbat]

Re: 1997 200 OceanPro surging at idle

I've had them out but to tell you the truth I've somewhat removed them from suspicion at this point. The reason why is because I've gotten the alarm on both the reserve and main tanks and the alarm seems only to occur once I get below a 1/2 tank of fuel or so.

The first time it happened I was trolling off the reserve tank which was low on fuel. The alarm went off and I switched over the main thank that was full and the alarm went away. It wasn?t until I let the main tank go below a ? tank a few weeks later I got the alarm again. Only this time it was coming up out of the hole on the way back to the marina. It was rough as a cob that day out on the open water and it would alarm at anything over @4000 rpm until we got back into the calm of the river and then it would run WOT for some reason.

It was at this time I tore everything part and blew everything out including the anti-siphon valve. I didn?t get another alarm again until last week when cruising back to the marina and decided to bumped the throttle from 4500 rpm up to WOT to ?blow the carbon out?. I bumped it back to 4500 rpm and it went away and ran fine the next day granted I never tried going over 4500 rpm.


I?m thinking that the pressure drop in the system caused by needing to lift the fuel and additional 8? or so from the ? tank of gas is putting it over the edge. I?m going to replace the anti-siphon, primer bulb, and hoses and by-pass the fuel selector valve for good luck and see what happens.

I may also remove the in-line filter from the fuel hose under the cover. I?m running a 10 um Racor so I?m thinking the filter under the cowl is redundant and isn?t helping with my fuel restriction. Is there any reason why I should leave the fuel filter under the cowl as well?

 

[ezeke]

Re: 1997 200 OceanPro surging at idle

I would agree on the extra filter; too much unnecessary resistance. The primer bulb staying hard would indicate a possible problem on the engine side as well.