Can't get the air out of oil line 1987 Suzuki DT85

[jim dozier]

I have a 1987 DT85 Suzuki with oil injection. I replaced the oil hoses and oil filter for general maintenance. I bled the oil pump as per the Clymer manual. The oil rose in the small oil lines until it got past the check valves and there is an air space in the larger tube that comes out of the checkvalve and goes to the intake manifold. I had it out all day on 50:1 premix and the air bubble wouldn't go away. I even pulled off the tube on the water let it fill up and as soon as I put it back on it gathers an air space. What is the deal here. The level in the oil tank is going down but I don't recall if there was an air bubble there before or not, the old tubes weren't very clear.

 

[fish4970]

Re: Can't get the air out of oil line 1987 Suzuki DT85

jim i have the same bubbles in my tubes<br />but never removed them<br /><br />thanks for the help with my overheating<br />problem<br />i pulled the head and the water jackets looked brand new<br />checked the temp switch / works fine<br />still lost<br /><br />think oil pump is bad just going to premix<br />don't have a manual could you tell me <br />what the WOT rpm shuld be so I can prop it right<br /><br />thanks a bunch<br /><br />this site is a wonderfull tool <br />hopefully someone can help you

 

[fish4970]

Re: Can't get the air out of oil line 1987 Suzuki DT85

Jim sorry to keep asking questions on your post<br />but i read on one of your other posts that you <br />installed a temp guage<br />what is your normal wot temp<br /><br />thanks

 

[jim dozier]

Re: Can't get the air out of oil line 1987 Suzuki DT85

Fish4970 I am having and have had problems with overheating at WOT on this engine. I had replaced the oil hoses while I had the powerhead off to replace a leaking engine holder gasket (which is beneath the power head gasket). This engine runs at about 185 degrees F. at 1/2 to 7/8 throttle but at WOT it creeps up to 200+ degrees F. and will set off the alarm (which by the way has been replaced) after 3 or 4 minutes. The engine runs pretty good otherwise. In an effort to fix this I have:<br />1. Replaced water pump impeller (twice). It overheated quickly when I bought it and replacing the water pump the first time really improved it, but eventually I noticed the WOT problem.<br />2. Replaced thermostat. Even tried it for a while without thermostat.<br />3. After consulting a Suzuki mechanic I replaced the head gasket with a newer OEM version and cleaned out the clogs in the head cooling passages.<br />4. Installed temp gauge.<br />5. Pulled the powerhead and replaced the exhaust cover gaskets and cleaned exhaust cooling passages.<br />6. Replaced temp sensor. This seemed to work for a while but the problem either returned or was still there and I just couldn't tell right away. <br />7. I should have replaced the engine holder gasket the first time I had the powerhead off but one mechanic said I wouldn't have to. He was wrong.<br />8. My other mechanic asked if I had properly installed the water bypass valve when I had the head off. I did but I am wondering if maybe the spring on the bypass valve is old and the valve is leaking too much at high speed. It is the only thing left in the cooling system that hasn't been replaced.<br /><br />This engine pees like a fire hose and I have I think eliminated every other possibility. I think I will remove the head one more time, have a machine shop plane it flat, and replace the bypass valve and spring and hope for the best. Anybody else have any thoughts about the overheating or the oil hose air bubble?

 

[jim dozier]

Re: Can't get the air out of oil line 1987 Suzuki DT85

^

 

[jim dozier]

Re: Can't get the air out of oil line 1987 Suzuki DT85

^

 

[jim dozier]

Re: Can't get the air out of oil line 1987 Suzuki DT85

Still looking for some info on the air space in the oil injection line at the intake manifold. I checked the pump and its pumping at the factory specs. My guess is that its not a problem, the oil is going somewhere, I guess the air is from the intake manifold. Just thought somebody would know.<br /><br />Fish4970 I may have some info for you on the overheating question. I backed off (retarded) the max advance on the ignition and now the engine temp isn't creeping up. I had not done that before because the timing was right on the mark, though I haven't ever checked it with the timing light which I plan to do now that I've changed it. I don't have a tach but I couldn't tell any difference in the performance, but I was able to blast around all day at WOT. Time will tell.

 

[fish4970]

Re: Can't get the air out of oil line 1987 Suzuki DT85

thanks jim <br />i ran it today & still same overheat above 4000<br />i have a timing light and will check this week<br />after i buy a factory book<br />really don't want to pull the powerhead if <br />not absolutely necessary <br />i have also been asking around about your<br />air bubbles but no new info<br /><br />jim could you tell me the factory recomended<br />wot rpm<br />thanks

 

[jim dozier]

Re: Can't get the air out of oil line 1987 Suzuki DT85

I don't know exactly, but it should be in the neighborhood of 5200-5600 rpm. In one on your other posts you were having difficulty with prop selecion and rpm. You were getting something like 40 mph at 4200 rpm which is too low an rpm for WOT. Clearly that prop is too much. What puzzled me is that you said you had another prop which would get you 5300 rpm which is in the right ballpark but you said it would only get you 30 mph. You should not have lost any speed going to the smaller pitch/diameter prop, in fact since you are now on top of the power curve at 5300 rpm I would have expected a slight improvement in speed. Something is not right in that picture. Think of it as downshifting to a lower gear in your car, as long as you are not exceeding the redline and the power curve of your engine you wouldn't lose any speed downshifting from 5th into 4th gear and in fact you would have more power.

 

[jim dozier]

Re: Can't get the air out of oil line 1987 Suzuki DT85

My Suzuki mechanic says that an air space between the check valve and the reed manifold is OK. Gravity and oil pressure drip the oil in the reed manifold.

 

[fish4970]

Re: Can't get the air out of oil line 1987 Suzuki DT85

jim i guess i shifted from overdrive to 2nd <br />i went from a 13x19 to a 13x15<br />i wonder is it ok for the cavitation plate to be<br />3/4" out of the water while cruising<br />could i be getting air in the system<br />that rises to the top above where the tattle tale<br />hose is conected<br />that way i would not see air in the pee

 

[jim dozier]

Re: Can't get the air out of oil line 1987 Suzuki DT85

I think the general rule is that the cavitation plate should be even with the bottom of the hull. You could be sucking air and cavitating which would result in slippage, overrevving, and sucking air into the cooling system. You might try posting this question on another post, there are people more knowledgeable about props and motor height than me. Good luck

 

[fish4970]

Re: Can't get the air out of oil line 1987 Suzuki DT85

thanks jim<br />i'll try that<br /><br />did you get a timing light

 

[jim dozier]

Re: Can't get the air out of oil line 1987 Suzuki DT85

Oh I have the timing light, the problem is I have to do it on the water at full throttle (advance) and I need someone to steer the boat. Not something you do in the driveway unless you have a test tank and a test prop. I am curious to see what the timing is in degrees after I retarded it about 1/16 back from the mark on the timer base, the book says its supposed to be 21 degrees BTDC at full advance.

 

[fish4970]

Re: Can't get the air out of oil line 1987 Suzuki DT85

jim when i set my 175 merc the book said to do it <br />with all the spark plugs out but #1 and at cranking speed with throttle wide open<br />it makes sense bocause timing position is linked with throttle not actual engine rpm<br />not shure if its the same for suzuki though

 

[jim dozier]

Re: Can't get the air out of oil line 1987 Suzuki DT85

I guess that would work. I may try that tommorow.

 

[fish4970]

Re: Can't get the air out of oil line 1987 Suzuki DT85

jim did nyou try the timing light<br />i did and it shows 27 BTDC<br />doesen't your book say it shuld be at 21 BTDC<br />thanks

 

[jim dozier]

Re: Can't get the air out of oil line 1987 Suzuki DT85

Yes I did the timing light last nite. It is now set at 18 deg BTDC which is 3 deg retarded from the 21 deg it is supposed to be set at. I don't have my manual if front of me, I'm at work, but I think I remember that different years had different timing. I know the 1986 model had 7 deg ATDC for the minimum advance at 1000 rpm and my 1987 model had 3 deg ATDC at 1000 rpm, so there might be a difference at the max end also.

 

[fish4970]

Re: Can't get the air out of oil line 1987 Suzuki DT85

jim one last question and i'll quit bothering you<br />did you use the timing procedure that i suggested<br />thanks again

 

[jim dozier]

Re: Can't get the air out of oil line 1987 Suzuki DT85

Sort of. I disconnected the carb from the timing/throttle linkage. I was able to crank up the engine on the muffs and give it full advance without the engine going over ~1500 rpms and took a timing reading with the engine running at full advance just not WOT or high rpms.