90 merc 2 stroke start problems

[thebulldog]

Hello
i have a 1994 merc 90 hp oil injected two stroke that is a real pain in the *** to get running, it has had a new ignition module, it has new high end gas with fuel conditioner. It will run and get going , it just has hesitation to run and you can smell the the fuel in the air, plugs are new, this is a three cylinder with carbs. When it gets up and go, it will smoke at low speeds, which is normal, but at near full speed there still is a low and visible amount of smoke.

Anyone have any ideas ?

 

[B-Dozer]

Re: 90 merc 2 stroke start problems

Have you done a compression check ? If it was me I would also unhook the oil injection and and try some good ole mix and see if that helps.

 

[Texasmark]

Re: 90 merc 2 stroke start problems

I have a '02 version of that engine and it too is cold natured. Tricky to get her to light off the first time in the outing. Once I do the first hole shot for the day, it is stellar the rest of the trip.

I use syn blend TCW-III "2 cycle water" oil in mine and it smokes less than plain old dino oil. The oiler on that engine varies the amount of blend from a lean 80:1 at idle to a richer 50:1 at WOT. The engine doesn't need the lube at idle and it helps to reduce the smoke. First hole shot I can look back and see an oil cloud but after that you really have to look for it. On smell, I doubt you can get down wind of any 2 cycle engine and not smell something. I have recently disabled my oiler, something less to worry about so I smoke a little more at idle that previously as I am running 50:1 all the time, but it still is barely noticeable.

Excessive smoke is trying to tell you something, but I don't have a quantitative value for your remark on the amount at WOT.

What are your rpms at WOT and how is your hole shot (getting the boat to plane)? What kind of boat is it on and what kind of load are you pushing. What kind of prop are you running and the pitch? What kind of fuel conditioner and how much?

Mark

 

[thebulldog]

Re: 90 merc 2 stroke start problems

Hello and Many Thanks B-Dozer and Mark, new to this type of motor/boat and it sure helps getting the lowdown from real folk w experience !
Mark, I am just about ready to install a new Tach/rpm as the one that came w it was smashed in, the boat is a Doral Splash (jet boat) very similar body/interior to Seadoo's, only 2 folk in the boat with no skiing, prop and pitch not quite sure of, and the fuel conditioner is Seafoams. I will do the compressions next week and try Syn Blend oil.

Many Thanks, The Next couple of rounds is on Me ! Bulldog

 

[Dave1027]

Re: 90 merc 2 stroke start problems

Maybe you have a carb that is flooding because of a stuck needle valve or a sunk float? Check the condition of the spark plugs. Is one more fouled than the rest? If so you may want to rebuild that carb with a new needle, seat and float.

 

[Silvertip]

Re: 90 merc 2 stroke start problems

Did this problem just occur or has it always been hard to start? Not to be critical but many starting issues are due to operator error which invites the question: What is your starting procedure (in detail please).

 

[thebulldog]

Re: 90 merc 2 stroke start problems

Hello Dave, Many thanks for the reply, i will take a good look at plugs which are the flat type without the gap, and are about a month old,
i will at the same time check compressions while at it, probably will do this next week and do a follow up on here with results.

Hi Silvertip, thank you for replying and helping, the motor has had issues w starting, a mechanic had it in the fall of last year with the main work order reading : poor starting, check carbs, change fuel and injector oil and smokes a lot, the work done was checkout and test ignition components and system. The work order also reads: Installed new switch box, startup and run, 3 and 3/4 hours at $79.99,
Labour $299.00 Parts $370.00 Total $ 760.00. I have also installed a brand new deep cell battery this year.

My startup procedure is while making sure gearbox in in neutral, to start the blowers 4 minutes before I turn the ignition switch on and engage the choke, also checking the battery and fuel guages, while i turn the motor over i watch the battery meter for power drop, I try for about 30 seconds wait 1.5 minute and repeat the cycle, which winds up to be about seven attempts. There is a fuel primer bulb which is also about a month old installed in the correct direction, I have found that using it usually floods the motor Badly and i might as well come back in an hour, I also open the throttle all the way while waiting to let air get in and vent. There are three carbs (Walbro side draft), the funny thing about the carb cover is that there is no filter in there its just flow through and the manual indicates no filter in the text/drawings. After it gets started and running it will fire up on the first key turn. This is a bothersome problem and seems to bother others that want to get to use the ramp dock zone, any help and ideas that are offered would be really be appreciated, Thank You Bulldog.

 

[thebulldog]

Re: 90 merc 2 stroke start problems

SUCCESS !
after 7 hrs and 3 beers, i checked plugs, compressions, hoses , wiring, carb linkages and anything else that was visible and had any sign of wear/tear, i opened the third beer, and was looking at the dash, i had a swig of beer and for some odd reason thought that hey ... i didnt crawl under the dash yet, so on my back, beer at my side, in cup holder of course (saftey First) I notice that the deadman wrist lanyard wiring had been worn through and with the wiring harness wire ties was barely making contact as the wire was just down to one last thin and broken wire, fix that up new and water & abrasion tight, a mouth of the golden ice cold beer, and one twist of the key .... SUCCESS!
Many Thanks to all that have given me insight and ......... A few rounds on Me ! Bulldog

 

[Dave1027]

Re: 90 merc 2 stroke start problems

My startup procedure is while making sure gearbox in in neutral, to start the blowers 4 minutes before I turn the ignition switch on and engage the choke, also checking the battery and fuel guages, while i turn the motor over i watch the battery meter for power drop, I try for about 30 seconds wait 1.5 minute and repeat the cycle, which winds up to be about seven attempts. There is a fuel primer bulb which is also about a month old installed in the correct direction, I have found that using it usually floods the motor Badly and i might as well come back in an hour, I also open the throttle all the way while waiting to let air get in and vent. There are three carbs (Walbro side draft), the funny thing about the carb cover is that there is no filter in there its just flow through and the manual indicates no filter in the text/drawings. .

Blowers? I don't understand that. Blowers are normally for sterndrive motors. They don't apply to outboards.
These motors do not use air filters. Not much dust out on the water to filter.

My cold starting precedure is this:

1) verify motor is trimed down
2) squeeze primer bulb till hard
3) Give a small amount of neutral throttle
4) Push key in (engages enrichener) and turn to start

Always fires quickly using that method