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Low rpm problem at wot

S

Sparky05

Member
I've had a problem with a 1094 evinrude intruder v6 for about if say I'm on my 4th year. I threw a rod they the block. I bought a rebuilt long block and sent it to one of our local shops to have him swap all the components. I got it back with strict break in direction, which I'm confident I did to a T. I brought the boat back to be retuned after the breakin as I was instructed. To the boat out after and my max rpms is 4300 and 34mph with a tail wind. I've brought it back I can't tell ya how many times, with no better results. I brought it to another highly recommend mechanic in another town. He changed all the fuel lines told me he got the tack to hit 5800 rpms should be good to go. I took the boat out the next weekend with high hopes. Hit the throttle and watch the rpms rip right up to 4300 rpms and hold tight there.. I bought a shop manual at this point and I'm slowly plugging away at what some of these forums are saying. I'm waiting on the vro rebuild kit to arrive that will be the next step I take. My fuel bowl before the pump had a leak I've handled that so far. I plan to pull my coils and test them according to the manual this week. Is there something else I should look at , to save some step to resolve this issue?
 
Well, for one thing, your engine is 925 years old (couldn't resist!) :) Seriously, what is that engine's model number?

On the back of that tachometer, there is usually a dial pertaining to charging pulses which is what the tachometer operates on. That dial should be set to six (6)... What is it set on?

Start with the basics:

Remove "all" spark plugs.

Compression - What are the "actual" compression psi readings of the individual cylinders? Note that standing in back of the engine, facing the spark plugs, the cylinders are numbered as follows:

2.....1
4.....3
6.....5

Ignition spark:
The spark, at cranking speed (300+ rpm) must jump a 7/16" air gap with a strong blue lightning like flame... a real SNAP! Does it? NOTE that the 7/16" air gap is important.

Regardless of ones intelligence, occasionally the wires from the powerpack to the coils get confused. They should be connected as: Orange/Blue=Top Cyl..... Orange=Center.... Orange/Green=Bottom (Check them).

Remove the carburetor face plate to check that the throttle butterflies are wide open (horizontal) when the throttle control handle is at full throttle (engine NOT running).

Reply in specifics... not generalities such as the compression is good, spark is great. This doesn't tell us anything.
********************
(Spark Tester - Home Made)
(J. Reeves)

You can use a medium size philips screwdriver (#2 I believe) inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark or build the following:

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:

..........X1..........X2

.................X..(grd)

..........X3..........X4

This can obviously be modified to a 6 or 8 cylinder setup tester.
********************
 
Last edited:
joereeves said:
Well, for one thing, your engine is 925 years old (couldn't resist!) :) Seriously, what is that engine's model number?

On the back of that tachometer, there is usually a dial pertaining to charging pulses which is what the tachometer operates on. That dial should be set to six (6)... What is it set on?

Start with the basics:

Remove "all" spark plugs.

Compression - What are the "actual" compression psi readings of the individual cylinders? Note that standing in back of the engine, facing the spark plugs, the cylinders are numbered as follows:

2.....1
4.....3
6.....5

Ignition spark:
The spark, at cranking speed (300+ rpm) must jump a 7/16" air gap with a strong blue lightning like flame... a real SNAP! Does it? NOTE that the 7/16" air gap is important.

Regardless of ones intelligence, occasionally the wires from the powerpack to the coils get confused. They should be connected as: Orange/Blue=Top Cyl..... Orange=Center.... Orange/Green=Bottom (Check them).

Remove the carburetor face plate to check that the throttle butterflies are wide open (horizontal) when the throttle control handle is at full throttle (engine NOT running).

Reply in specifics... not generalities such as the compression is good, spark is great. This doesn't tell us anything.
********************
(Spark Tester - Home Made)
(J. Reeves)

You can use a medium size philips screwdriver (#2 I believe) inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark or build the following:

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:

..........X1..........X2

.................X..(grd)

..........X3..........X4

This can obviously be modified to a 6 or 8 cylinder setup tester.
********************
Click to expand...
Yikes sorry it's a 1994 lol model is E150Glerv. I was told obviously by the mechanics that compression was good. But I can certainly check it out my self. The engine is very reliable starts and idles what I think is ok. From idle say if you pull a skier at taking off hesitate for a sec then takes off. From little over half throttle push it to full it hesitation again. Then hardly has any rpm gain, the tank anti siphon is gone and the pickup screen as far as I can see I just have a tube going into the tank, I will admit I probably need to clean the tank since I personally never have nor do I know that it has been done. I check and clean filter regularly and it is picking up dirt or stuff from in the tank. But I have had this problem from day one of my rebuild completion. I will get after your suggestions and get back to you with my results, I appreciate your help and patience. Thank you.
 
Ok so I noticed I may need new compression tester, instead of needle on 0 it sits on right at 14-15 psi. With that being said and the fact I may need to Decarb this motor after looking in cylinders,
cylinder-2 showed 89psi adding the 15 104psi
cylinder-4 was 89+15--104
cylinder-6 was 89+15=104

cylinder -1 was 91+15= 106psi
cylinder-3 was 91+15= 106
cylinder-5 was 90+15=105psi
i didn't get to the spark test tonight. I will get a new compression test gauge this weekend and redo those cylinders.
 
joereeves said:
Is that tachometer set properly?[/QUOTE
I did no look to see if the tach is set on 6. I ran out of what my wife calls free time lol. it will be rare for me to get a big block of time at once to complete all test in one shot. just wanna let those helping me as to not give up on me.
Click to expand...
 
joereeves said:
And when you are out of "free time".... you are doing what? :)
Click to expand...

electrical foreman by day, ranch hand to the wife after that. But I will stay focused on this its a real bother to me. the motor runs ok and it reliable but I know it not running like I believe it should.
 
no sir it has not ran the same since I got the long bock swapped out, obviously different block I understand, performance wise not at all what I had..
 
Question?....... The problem that caused your original powerhead to blow?... Was that problem discovered and corrected... OR... was everything just changed over to the replacement powerhead? If NOT discovered and corrected, you have simply transferred the original problem to the 2nd powerhead.

If you did not check the spark yet as I suggested (7/16" gap), do so as it is important.

The hesitation... I understand that to be a momentarily thing when full throttle is given... just for as second, then it picks up and goes to full throttle as normal....... It DOES NOT die out whereas you are forced to play with the throttle to keep it running. If I understand properly............

That scenario is usually caused by a sticking timer base, if so equipped, (timing advance) under the flywheel. Advance the throttle (engine NOT running) and observe the timing base.

Also look closely at the stator to see if there is a sticky looking substance dripping down on the timer base (meltdown) and powerhead area. If this exists, that sticky looking substance is no doubt what would be causing the timer-base to stick. If the stator is as described here, it will require replacing.

Let us know what you find.
 
the original engine obviously had some hours on it. It as hard to keep running at just in gar idle.I ended putting a new power pack on it the first year I had it. by mechanics advise I went to premixing oil to avoid VRO failure at that time. the power and rpms were never an issue I'm pretty sure the high hours and my playing with the kids on the tube was the cause of the rod finding its way thru the side of the block. This new motor idles steady just the hesitation out of the hole, and from half to full throttle, so I will check your suggestion. the only issue I have with this motor/rebuild power head is since the swap it has never seen over 4300 rpm nor over 34-35 mph. old power head easy 6000 rpms 17 pitch prop for quick hole shots. and I hit 53 mph by myself in it. During tear down for swap mechanic said that 2 cylinders were bored and repaired this is in blown up block. so hopefully your not right about transferring problem. Im hoping the old was just tired, add my running things a bit hard. ive got all your instructions and advice on a list and I will perform them and get back to you with the results asap. I do know the original mechanic was swapping parts from his Johnson 150 to mine for trouble shooting purpose, maybe he has a great new component running motor. jk. Is there another way of figuring out model number besides the sticker on trandsom? mine is wore out that you cant read the numbers. I assume with the new block I do not have original serial number in the frost plug. or am I dumb about that thought?
 
I, and other mechanics that worked with me always removed the core plug from the blown powerhead and installed it in the new powerhead so as to have the numbers to be identical on the transom bracket or wherever the engineers decided to put the ID plate that particular year. Not a lot of people go to this trouble... it varies.

Question: That 1994 Intruder V6... Is that a crossflow or a looper?.... Crossflow has 3 aluminum carburetors.... Looper has 6 plastic carburetors.

Add to your list (after running the engine hopefully) remove the spark plugs, examine them closely, make a note as to what cylinder they came out of. My reasoning is that I'm wondering exactly what the exact top rated rpm is... If you know what that maximum rpm is, let us know.

FYI... As a reminder, the cylinders are numbered as follows:

2.....1
4.....3
6.....5
 
joereeves said:
I, and other mechanics that worked with me always removed the core plug from the blown powerhead and installed it in the new powerhead so as to have the numbers to be identical on the transom bracket or wherever the engineers decided to put the ID plate that particular year. Not a lot of people go to this trouble... it varies.

Question: That 1994 Intruder V6... Is that a crossflow or a looper?.... Crossflow has 3 aluminum carburetors.... Looper has 6 plastic carburetors.

Add to your list (after running the engine hopefully) remove the spark plugs, examine them closely, make a note as to what cylinder they came out of. My reasoning is that I'm wondering exactly what the exact top rated rpm is... If you know what that maximum rpm is, let us know.

FYI... As a reminder, the cylinders are numbered as follows:

2.....1
4.....3
6.....5
Click to expand...
its a looper/ 6 plastic carbs. Not sure if this matters but I believe it's the quiet rider also, I realized that today.
 
You have the optical sysem and its on top of flywheel...rarely sticks. Did you install oversize pistons in the bored holes? Sound like you have mechanical issues such as wrong piston size or piston installed upside down.
 
Ok cool, I've built race car motors for myself, diesel truck motors and motors for haul trucks for the mines. I don't mean to question your knowledge at all but dos I read your post correctly? That boat motor Pistons can be installed upside down? I ask cause I've never built a boat motor nor have I ever seen one even tore down other than pics
 
Yes they can be installed upside down as skirt has notches for porting in block, wont run worth a dang, also could have one on wrong side as they are side specific.
 
Agreed there are 3 pistons marked for port side and 3 for starboard.-----So yes they can be installed wong !!-----I doubt that a shop would have made that mistake.
 
Since I've just found that this is a looper with the optical system, of which I am not familiar with... I'll back out of here and leave the thread to the more knowledgeable members.
 
Bullet... At Pioneer Marine in Tampa (now defunct), somewhere in the 1980's, a brand new 70hp or 75hp (I forget which), straight out of the box, just installed by the riggers.... they couldn't get it running properly worth a damn and called me to check it out.

Everything checked out as it should BUT #3 cylinder was worthless. Now, they (OMC) always said that each engine was run out before being packaged but the way that engine acted, killed that claim. IN desperation, I removed the cylinder head.............

#1 & #2 piston was marked at the top "up" and "up"..... #3 was marked at the bottom "dn". I had OMC on the horn... they exclaimed in strong wording that was impossible, in effect calling me and my fellow workers liars. I didn't take too kindly about that. Next on the phone was the president of Pioneer......
dn
 
Okay, so that's not encouraging lol, is there a way to test without pulling head off? Would compression still be in the range? Apparently so if my numbers are all in the range as listed than it is possible. when I do get wot and planed out, the motor kinda has a lurch every so often like it want to just jump forward, for a split second, I've got this month yet to fish maybe two weeks , I was hoping it was like an electrical issue, bad coil or power pack or something, poorly installed piston now that you guys have explained it, wow I never would have remotely come to that conclusion.. The original mechanic said he did all the tests electrically and all tested good he threw his hands up and felt I had a faulty power head, course by this time out of warranty lol. If you guys are right I'll be taking trip to him with an apology lol.. If I just pull the head since it looks painless, what am I looking for will I be able to rule this out or find the issues if I just pull the head as Joe said?
 
Ok I'll go to town and get some black rtv, and sea foam spray to clean off the Pistons, what will I be looking for? I'm assuming markings on top of piston?
 
They will have UP etched in them at 12oclock or if aftermarket the word UP/U or a arrow pointing to center of motor(exhaust). Also will have at 6 oclock a S or P to mark port or starboard side. You never replied if oversize pistons was installed in the bored cylinders.
 
Awesome thanks for the info, I'll hopefully have the vro pump built and back on by Monday, I'll run a half gal mixture for Decarb purpose so I can even see what your speaking of. It looked dirty when I checked compression. I will get back to you with what I find ASAP. Thanx again for everyone's input, and guidance. I appreciate it.
 
As far as your question to if I have oversized Pistons, it's been 4 years since I got the power head I truly don't remember but I'm assuming so, I do remember it was sold as a complete remanufactured not a rebuild. So I was thinking it is bored oversized and all new Pistons. But that should be marked on the piston also correct? If it's like a vehicle that I know what I'm looking for lol.
 
I assume 12 o'clock being the top of the motor ? If I'm standing behind it and I'm on the ground, I just want to be clear since this does sound like it's pretty important that things /are in the correct locations
 
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