200HP suzuki dies under load

[murphy1]

Hello, this is my first post and I've done a lot of reading of other posts to solve my problem, but still stumped. I have a 1987 dt200 that starts and idles fine. When I put it in gear it dies out. So from reading other similar posts, I took the advise and cleaned the carbs. They were very clean upon inspection, but took the floats and needles out of all 3 and ran some carb cleaner through them anyway. Reinstalled and problem persists. I could always keep the engine going under load if I hit the purge switch to shoot more gas in, which leads me to believe that it's running lean. So I backed off the screws a full turn on all three, did nothing, after another turn to make it richer, still same problem. What's confusing is that it runs great through the rpm range not in gear and IF I get it on plane it runs great. All fuel line and tank have been replaced. I have a fresh 40 gallons in there now with 2 cans of Sea Foam, so I'm stumped. If this helps, this problem started at the end of last season when it started getting cold. Any ideas? Is there a way to test the mechanical fuel pumps? It really seems like it's starving for fuel?

 

[murphy1]

Re: 200HP suzuki dies under load

Does anyone know how much a carb rebuild kit goes for and where you can order one online?

 

[fireproducts100]

Re: 200HP suzuki dies under load

rebuild the carbs and look and see if your spark plugs are gapped right not sure of the correct gap on a 87 200hp

 

[clanton]

Re: 200HP suzuki dies under load

Do you have spark all cylinders 1500 and 2000 rpms?

 

[murphy1]

Re: 200HP suzuki dies under load

It runs perfect throughout the rpm range in neutral, so I would assume so. how would I ever test that?

 

[jim dozier]

Re: 200HP suzuki dies under load

You may need to redo the carb cleaning rebuild. It sounds like the idle circuits are still in need of cleaning. You can't always tell if a carb is clean by looking. Its not a beauty contest, we are talking about small deposits in the idle orifices where you may or may not be able to see them. If you go to the trouble of disassembling the carbs make sure you clean ALL of the orifices with carb cleaner and compressed air. I'm not sure about that particular carb but the Mikuni carbs on my Suzuki DT85 have idle mixture screws that meter air not fuel so you would screw them in to enrichen the mixture. If that's the case you are making the problem worse by unscrewing the idle screw. Check your manual for the proper procedure. Go to the bottom of this web page and order a manual if you don't have one. <br /><br />It doesn't matter that the engine revs in neutral. Never evaluate an engine in neutral except just to see that it runs. The engine needs to be in the water (backpressure) and under load (in gear) to set the idle mixture and speed.<br /><br />You can check the fuel pump by pumping the fuel bulb when the engine falters or by loosening the screws that attach it to the block and pumping the bulb to check for leaks in the diaphragm. I'm betting its the idle circuits in the carbs though.

 

[phatmanmike]

Re: 200HP suzuki dies under load

www.brownspoint.com browns point marina in newjersy

 

[murphy1]

Re: 200HP suzuki dies under load

Thanks for all that info. I actually gave up and brought it to the mechanic and just got off the phone with them. What scares me is that they said all they did was change the plugs (which i did last week) and reset the idle air screws. They never put any load on the engine to test it though. they said it's running great now. Wanna place any bets on what happens when I take it home and put it in the water? I'll let you know after this weekend.

 

[ThomWV]

Re: 200HP suzuki dies under load

When I have done those carbs I actually run pressure water into the bleed holes (where the screws go in) and then look for water comming out of the 4 or 6 holes in the venturi, just where the butterfly valve would strike with a closed throtle. That is where the gas passes and gets into the airstream on the idle and intermediate circuit but it also contributes fuel to the system at high speed as well. Make sure they are clear. After that look closely at the throtle position sensor on the bottom carb. Are you setting it to 240 ohms? It is that sensor that controls your ignition advance and basically controls the engine's performance from one end of the scale to the other.<br /><br />Thom

 

[jim dozier]

Re: 200HP suzuki dies under load

It may be that all that was necessary was to turn the idle air screws the opposite direction than you did to enrichen the idle mixture. A good mechanic would have done so in a water tank not on the muffs. Hope for the best. Buy a manual, do it yourself next time <br /><br />Did you put in the correct spark plugs gapped correctly? Did they replace them with the right ones?

 

[murphy1]

Re: 200HP suzuki dies under load

I appreciate all the feedback. I'll give it more of an effort next time. At least I'm educated on what to try now. I am just pressed for time, the boat is an hour away from where I live, making it hard to work on, and the co-owner, who used the boat once a year, expects it to be ready for him each time he uses it. So we'll see come this weekend if the $85/hr was worth it, haha

 

[clanton]

Re: 200HP suzuki dies under load

You can check the spark with a timing light. I dont have time to look at a service manual. I just went thru a 1990 Super Six, twin plug head. There were a lot of changes in the ignition system up to 91/92. If your engine has an ignition control module on the strb side of the engine, you need a manual, peak reading meter, and start checking the voltage. There were no specs in the manual for the icm, you need .02 volts here at cranking rpms, and may go to .06 at idle. If the stator has seperate coils that can be replaced, then remove the flywheel, and check the ignition charge coil and the IC coil, if the insulation has the least amount of burn color like toast, replace them. The IC coil makes power for the icm, which controls the timing, and triggers the cdi pack.

 

[murphy1]

Re: 200HP suzuki dies under load

Well, got the boat back and tested it this weekend. They adjusted the idle air screws and replaced the plugs. It idles nice, but as you can guess since I'm writing again, it still boggs down and stalls when you put a load on it. So, one thing I did from reading another post was to disconnect the throttle position sensor, which adjusts the timing. By doing this, I was able to put it in gear w/o stalling. I could only go about 7 knots, around 1500 rpm's before it bogged down again. If I gave it full throttle I was able to get the boat on plane. But, it was either you go full throttle or a max of 7 knots, there was no midrange. Any ideas from that synopsis? If anyone comes back telling me to test it with an ohm meter, please explain like you're talking to a 5 year old.

 

[clanton]

Re: 200HP suzuki dies under load

You need to check the spark with a gap tester, at cranking rpms. If you have spark at all cylinders, then check spark with a timing light at 1500, and 3000 rpms. An ohm meter is not going to help much with engine. You need to also check the output voltage from all sensors, charge coil,ic coil, and cdi, engine runing at idle and up to 3000 rpms. I looked in manual, the charge coil and ic coil come as seperate parts. about 60.00 each.

 

[ThomWV]

Re: 200HP suzuki dies under load

When you unplug the throtle position sensor you will see several (4?) wires that go into the plug. One of them is black and one of them is green and red. Put the black probe from an ohm meter inside the plug so that it touchs the metal strip for the black wire. Take the red probe for the ohm meter and have it tough the contact for the green/red wire.<br /><br />Disconnect the lowest arm for the throtle linkage so you can move the throtles by hand by grabbing the linkage that connects the 3 carbs. Open them up and then let it go so they snap shut. You can not test the throtle position sensor's setting unless the throtles are completely closes (check that set screw on the to carb to make sure its not holding them open). Now, with the throtle butterfly valves fully shut the reading you get should be 240 ohms. If it is not loosen the three screws that hold it in place and do your thing until it is and until it holds that reading when you tighten it down. As you will see the reading changes as you tighten it down, so you have to play with it.<br /><br />All that said, it may be the sensor, and it needs looking at anyway, but what you describe indicates that no one has bothered to clean out those fuel feed holes in the carb's ventury. Take a paper clip to them if nothing else. Look particularly close at the middle set of holes.<br /><br />Thom

 

[murphy1]

Re: 200HP suzuki dies under load

I'll try all that advise tomorrow night, the testing and cleaning. Don't roll your eyes, but is there a setting on my mutimeter for the range of the ohms? or is there only one ohm setting? I actually ordered a new throttle valve sensor and it should arrive tomorrow. Do I have to set it like you stated even though it's new or does it come from the factory preset?

 

[ThomWV]

Re: 200HP suzuki dies under load

You have to set it. It is an adjustment, not a setting. If you don't do it you'll be lucky to get the engine to start, let alone run. I have no idea what multi meter you have so I could not tell you how to hook it up. Here is a hint though, if there are multiple plugs where you can plug in the positive probe look for one that has a symbol that looks like an upside down horse shoe over it, use that one. Don't worry about doing damage to either the guage or to the sensor,you won't hurt them.<br /><br />Thom

 

[murphy1]

Re: 200HP suzuki dies under load

Hey, I just wanted to thank everyone for their help. I got the new throttle position sensor from Browns Point and threw that it and the engine runs great now. I didn't have to adjust it at all, so I must have lucked out. So, all that trouble for a $40 sensor. Now, what do I do about my bill from the suzuki mechanic that didn't fix the problem?