90hp Two stroke,Will not plane.PLEASE HELP!!

[daveswaves]

Re: 90hp Two stroke,Will not plane.PLEASE HELP!!

Hey People.

I'v been messing round with the motor today,and found some Interesting thing's that might be contributing to my problem .Well i started the engine then one bye one took the lead's off each plug listning for any change in sound and performance,the bottom cyclinder i had problems with the intrusion of water on that spark was good decrease in performance as you would exspect so as the middle cyclinder but the top cylinder had no change in noise when i pulled off the lead.Im guessing a dead cylinder,Also i was getting a shock from the leed everytime i touched it,even pulling it off with vice grips that has a rubber handle.It seems like there is spark going into the lead but im thinking most of the spark is coming out the leed somewere,why im getting a electic shock.I'm going to swap leads around tonite and see if i will get a change.I just working up the courage to do it as it hurt like hell!!!...Should i buy a new power pak? and wires??..My mechanic Told me to look into the reed valve mite be a problem there.

Thanks,Thomas

It could be as simple as a bad plug, if the spark has no where to go you are the next best thing when you pull the lead, and yes, it hurts. Since it is night time over there right now, run the engine with the cover off and see if you can see the spark juming to ground where it shouldnt be. All of this makes sense since your planing problem, no matter how you slice it, is not enough power/thrust to do the job at hand. A dead cyl would certainly fit that description. It surprises me that you could still turn 5200 rpm with one dead cyl. None the less, it sure sounds like you are on to the problem.

 

[Texasmark]

Re: 90hp Two stroke,Will not plane.PLEASE HELP!!

When you say swap wires around I am assuming that you mean that you are going to physically unplug a pair of pulse modules, both input and output wiring, and physically swap their locations and reconnect accordingly. Course I don't think the plug wires on the pulse packs are long enough for you to just swap plug wires without doing anything else which you obviously don't want to do.

Agree with dave on the shock and the plug possibly not firing. The ignition system puts out 40kv and if the plug doesn't fire that's what's on the plug cap and that little bit of rubber is little consolation. If the plug does fire normally, then it fires somewhere around 15 to 20k and the rubber boot usually can hold that off.

Run the test like I said and if you get a super spark (compared to the other two) on the plug where you got shocked, then that is proof positive, time for a new plug. No need to swap modules, this is quick and tells you that your modules are working at the same time.

Course if the plug is fouled out it could cause the test to look like a bad module because the plug could be shorting out the spark.

Why don't you just bite the bullet and put in a set of new plugs and be done with it, unless you just put in a new set. Then if that doesn't do it keep looking.

Mark

 

[daveswaves]

Re: 90hp Two stroke,Will not plane.PLEASE HELP!!

When you say swap wires around I am assuming that you mean that you are going to physically unplug a pair of pulse modules, both input and output wiring, and physically swap their locations and reconnect accordingly. Course I don't think the plug wires on the pulse packs are long enough for you to just swap plug wires without doing anything else which you obviously don't want to do.

Agree with dave on the shock and the plug possibly not firing. The ignition system puts out 40kv and if the plug doesn't fire that's what's on the plug cap and that little bit of rubber is little consolation. If the plug does fire normally, then it fires somewhere around 15 to 20k and the rubber boot usually can hold that off.

Run the test like I said and if you get a super spark (compared to the other two) on the plug where you got shocked, then that is proof positive, time for a new plug. No need to swap modules, this is quick and tells you that your modules are working at the same time.

Course if the plug is fouled out it could cause the test to look like a bad module because the plug could be shorting out the spark.

Why don't you just bite the bullet and put in a set of new plugs and be done with it, unless you just put in a new set. Then if that doesn't do it keep looking.

Mark

Agree with Mark on the new plugs, it may be the only way to tell. A plug can misfire under compression and look fine when you are testing it out of the engine. Heres a bit of wisdom that my Dad shared with me regarding plugs, granted it was 1960 or so but it still holds true. " remove the plug and place is very very carefully on the surface of the lake, Let go quickly, if the plug floats it is good".

 

[Plyliteblue]

Re: 90hp Two stroke,Will not plane.PLEASE HELP!!

I have replaced the spark plugs a week ago and just out of curiosity i replaced them with spare new ones i had.no change.i swaped the spark lead's around and was getting no shock, cyclinder seemed to fire up,.So done a spark test was good same bright blue spark on all the cyclinders.I took it down to the lake this morning as i live on the beach and still the problem is there.I'm going to get freind who is a automotive electrician to run some test's even though the mechanic checked and said was good.If electrics are good then i'm stumped.I'm really hoping it is not Internal.

Thomas,

 

[daveswaves]

Re: 90hp Two stroke,Will not plane.PLEASE HELP!!

I have replaced the spark plugs a week ago and just out of curiosity i replaced them with spare new ones i had.no change.i swaped the spark lead's around and was getting no shock, cyclinder seemed to fire up,.So done a spark test was good same bright blue spark on all the cyclinders.I took it down to the lake this morning as i live on the beach and still the problem is there.I'm going to get freind who is a automotive electrician to run some test's even though the mechanic checked and said was good.If electrics are good then i'm stumped.I'm really hoping it is not Internal.

Thomas,

Make sure your friend reads all the posts here as well. Im a bit puzzled, the last post you had a cyl that did not change when you pulled the wire, after changing the plugs did you test it pulling the wire off again to see if one cyl did not make a difference? If so, was it the same cyl as before? Did you call the boat rental place with the same boat as yours and roughly the same engine to ask questions regarding expectations of your boat with that horsepower?
Your automotive mechanic friend should be able to tell if there is an internal problem with the engine. A compression test is in order again, I know your mechanic (marine) did one but you need to start the troubleshooting again with a logical approach.

 

[Plyliteblue]

Re: 90hp Two stroke,Will not plane.PLEASE HELP!!

Hi sori for the confusion,What is now happening is that the cylinder that was not firing yesterday is now firing as i have change leads and replaced the week old spark plugs with brand new spark plug's.There is now a noticable change in engine tone aspose to when i was running it yesterday When disconnecting the lead to that cyclinder ,giving me an asumption that cylinder is now firing.But i have noticed no change in performance when im at full throttle on the water.I have Talked to the guys at Hireaboat.co.nz and they have a max load in there plylite fisherman of four adults and planes the boat easily.i described my problem and said exacly what you guys have told me Prop,spark..etc

 

[daveswaves]

Re: 90hp Two stroke,Will not plane.PLEASE HELP!!

Hi sori for the confusion,What is now happening is that the cylinder that was not firing yesterday is now firing as i have change leads and replaced the week old spark plugs with brand new spark plug's.There is now a noticable change in engine tone aspose to when i was running it yesterday When disconnecting the lead to that cyclinder ,giving me an asumption that cylinder is now firing.But i have noticed no change in performance when im at full throttle on the water.I have Talked to the guys at Hireaboat.co.nz and they have a max load in there plylite fisherman of four adults and planes the boat easily.i described my problem and said exacly what you guys have told me Prop,spark..etc

OK, great, bear in mind that we (everybody involved in this thread) are trying to troubleshoot this from a distance and our only input is what you report. If we go back to some of your original posts this engine had a whale tail on it and a turbo lazer 11 prop, indications that the previous owner was trying to solve the same problems that you are. Im glad you called the Hire aboat guys, they at least have confirmed that your boat should plane no problem with 4 people in it with a 70 hp, you are working with a 90 HP so clearly something is not right. Everything is pointing to the engine not making enough power to push your boat. You have already had problems with one cyl dropping out due to water from a bad gasket. You have a cyl or spark plug fail at idle on the muffs, a different cylinder. We need your mechanic friend ( the one who works for free like us) to verify that the compression on all 3 cyl is even and adequate. We need NUMBERS. Either that or you could fly all us folks that are currently experiencing winter down to NZ and we will all get on your boat and fix it.

 

[Texasmark]

Re: 90hp Two stroke,Will not plane.PLEASE HELP!!

As far as I am concerned your problem is not ignition associated; you just proved that. Look elsewhere.

Mark