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What's wrong?

C

camoto

Member
I have a 1987 Checkmate with a 2.0L V150 and an OMC Powerlift. This thing REFUSES to pull a skier out of the water. Saturday I had a 4-blade Trophy 26p Prop on it and it just would not pull out a skiier. I tried every combination of trim and lift and the engine just bogs and will not get "over the hump". So then yesterday (Sunday) I go out and buy a 21p 3-blade aluminum prop. There was a noticeable difference in top speed, but bottom end seemed EXACTLY the same. So now I am starting to wonder if it is an engine problem.

If I put the motor all the way down on the powerlift and trim it all the way in, the engine dies. Someone told me that there may be something with the needle valve if that happens but I don't see how that makes sense. I do however agree that that seems wrong, because if the powerlift was not on the boat, I would be having the same issue, because the powerlift does not go lower than the original transom mount would be.

The strange thing is that if I am not pulling a skiier, it seems to plane out fairly quickly. Sometimes the engine will bog a little, but not too bad. Once you get the boat on plane, it runs fantastic.

Am I wrong? I would think a 150 on a 17' boat would rip a skiers arms off. This thing is pathetic. I have been able to do slalom starts for 20 years now and this thing cannot get me out of the water on two skis!

What's wrong???
 
only three things can be wrong. compression, fuel, ignition. start with a compression test - it's an easy test to do, if that checks out i'd move on to ignition - check for spark with a spark tester, again another easy test. then check fuel. as a guess, i'm thinking you'll find a fuel issue, however, it doesn't hurt to be thorough.
 
Chris E said:
only three things can be wrong. compression, fuel, ignition. start with a compression test - it's an easy test to do, if that checks out i'd move on to ignition - check for spark with a spark tester, again another easy test. then check fuel. as a guess, i'm thinking you'll find a fuel issue, however, it doesn't hurt to be thorough.
Click to expand...
Hi Chris, thanks for the reply!

So you think this is a motor issue? I am starting to lean that way too. The only thing that is confusing me is the fact that once on plane, the boat runs fantastic... But the part about it not running with the motor all the way down and trimmed in seems strange to me.
 
Hey Camoto, I have a simular problem with my 115 Johnson. I noticed that when the engine is at an idle and if the exshaust gets submerged the engine will stall. I have not checked my compression yet but, about fifteen yrs ago my grandpa had the same engine I do on a heavy 19ft Cuddy and it would pull a skier up with no prob. at all. I have to prop way down to pull a skier with mine.
 
83PREDICTOR said:
Hey Camoto, I have a simular problem with my 115 Johnson. I noticed that when the engine is at an idle and if the exshaust gets submerged the engine will stall. I have not checked my compression yet but, about fifteen yrs ago my grandpa had the same engine I do on a heavy 19ft Cuddy and it would pull a skier up with no prob. at all. I have to prop way down to pull a skier with mine.
Click to expand...

Hmmm, so if that behavior is normal, then maybe it's NOT the motor. I don't know, I am kind of at a loss. Part of me says the powerlift is just getting in the way. I really don't need to go 65 mph, I just want to be able to ski and have fun. Fast is cool for a few minutes and then it gets old. If I wanted to do 100, I'd just take my Ducati out to the track. I want to ski! LOL

The weird part is that if I put the powerlift down all the way and trim the motor in as far as it will go without dying, the boat still won't pull a skier out of the water. BUT, if there is no skier back there it will plane out after about 15 seconds and take off.
 
i'm wondering if the extra load is causing the problem - that's why i'm leaning towards the engine.
 
Chris E said:
i'm wondering if the extra load is causing the problem - that's why i'm leaning towards the engine.
Click to expand...
Well the only background I have is that Boston Predictor had the boat first, and said he had checked the compression and it was OK. I have replaced the plugs and wires, replaced all the fuel lines (because they were all rotted from the alcohol) and cleaned the carbs, bowls, float valves and jets. It idles smooth and once going (planed out) runs great. I will do a compression test on it myself and check it. It does bog sometimes almost like an engine with a stuck choke. I am wondering if the jetting could be off too. I don't think it would be a spark issue because it does idle smooth when it idles. I don't really know though at this point. I am grasping at straws.
 
I dont think its a motor issue myself, I think the trophy plus is a great prop(thats what I run). But, a 26p on a 150 trying to pull askier is just two much. I would look into maybe a 24p trophy for skiing. Or even a laser II 25p(23p). Id say your motor i more then likely fine just set up for top speed. Its not that the boat is only 17ft it always comes down to power to weight ratio. I think youll be happy if ya get a second prop for skiing and run the rophy otherwise. Aaron
 
aaronmt said:
I dont think its a motor issue myself, I think the trophy plus is a great prop(thats what I run). But, a 26p on a 150 trying to pull askier is just two much. I would look into maybe a 24p trophy for skiing. Or even a laser II 25p(23p). Id say your motor i more then likely fine just set up for top speed. Its not that the boat is only 17ft it always comes down to power to weight ratio. I think youll be happy if ya get a second prop for skiing and run the rophy otherwise. Aaron
Click to expand...

If that was the case, wouldn't the 3-blade 21 alum prop have at least helped a LITTLE bit? The only two things I noticed with the 21 was lower top speed and some cavitation in certain situations, but it didn't feel a bit different otherwise.
 
aluminum

the aluminum prop is not the right shape or your rig

it is probably a round ear made for a stern drive or a pontoon

the higher the rake the more bow lift the faster it will plane

on my v-4 i could run a 22 raker but i had a 20 raker for skiing

usually i had to come up on 2 and kick off

see if someone has one you can try

laser2 or trophy in a 23 keep the jack plate

you might not need all the way down but it will need to be fairly deep to pull skiers

good luck daren
 
15 seconds is forever just to get planned out. you should see 30 in 5 to 6 seconds even with a skier. post the results of the compression test. A weak cyl might only really bog down the boat under the added load
 
holeshot

Xsive, the motor is not stock, it was rebuilt top to bottom in 03 with good aftermarket parts, it should be pushing 200+hp

I dont think the compression is bad, it was tested last June when I had the stator done, and was perfect across the board, and wasnt really used much after I had it checked. I maybe put 10hrs on it last summer if that...Sounds like the exhaust is getting burried in the wake and bogging the motor...???


Ive always had bad holeshot w/ checkmates for some reason.. my predictor with a 135hp, 90hp, 80hp, AND the rebuilt 150 were all pretty bad compared to most other performance boats. I dont think its the motor, might be the setup?...The best holeshot I had in the sportfire was with a worked 28p hoss chopper oddly enough, and the jackplate ALL the way up(oppisite of what Ive been told to do on this site). I traded that prop for a 26p hoss and the holeshot was even worse to my suprise... it would rev like a mofo and then catch at 5500rpm after a few seconds. I tried a 25p stainless (like a lazer II) and that was the worst. The holeshot was especially bad with a full load. Sometimes I would have to stand up and lean over the windshield to get it on plane. The trick I found to get on plane fastest,(unless I had 4 people in the boat).... was jack the motor ALL the way up w/ a little positive trim. It should shoot right up on plane faster because it will have LESS bow rise...

The only thing I can suggest that will help for sure, is get a gas tank that mounts under the bow. Get all that weight out of the stern and move some to the bow. I know small checkmates are famous for their bows going way up in the air when planing, so it always helps to have some extra weight in the bow to keep it down and help you get over the hump. Try testing this first by having your buddy climb under there...Having weight in the bow will also help the handeling when skiing.
I dont know what else to say, I wish I had a definite answer. That much tourque should launch the boat out of the water like a rocket, but it doesn't...
 
is there anyone else who has a sportfire with a 150 or less on the back that can tell me if any of this is right?? It seems I get conflicting answers on every question about this situation.

My main concerns are:

a.) is it normal/correct for the engine to die at idle when trimmmed all the way in. (If not, something is wrong)

b.) Can a sportfire pull a skier out of the water with a 150 and a 21p prop. (I highly doubt prop shape would have THAT much of an effect)

c.) If the answer to B is "no" does anyone want to buy a sportfire?

I certainly am NOT moving the gas tank on this boat just so it will pull a skier out of the water. That's just plain stupid. My buddy has a 21' Key west with an 80 gallon tank that will rip your arms off and it has a 150 with a 19p. It makes zero sense that a tiny sportfire can't get out of its own way.

Some other possibilities I have found on screamandfly that I think MIGHT be applicable:

1.) Compression Issue
2.) Spark Issue
3.) Fuel Starvation
4.) Timing Advance linkage (does this motor even have this)


Lastly, I am wondering if the powerlift would be having a negative effect on pulling a skier. If so, it's coming off the boat.


Thanks so far to everyone who has added input, everything helps at this point.
 
Boston Predictor said:
Xsive, the motor is not stock, it was rebuilt top to bottom in 03 with good aftermarket parts, it should be pushing 200+hp
Click to expand...

So what was done to give it 200+ hp?

Camoto,

It is quite possible that it is normal to die when the jackplate is all the way down and trimmed in. What is likely happening is the idle exhaust relief is getting buried in the water instead of being above it and it is creating backpressure causing it to die. There could be other issues.

A Predictor with a 150 should be a great ski boat. Something ain't right. If your jackplate is only 6" then it should be fine on that boat.
 
It's a sportfire, not a predictor... which should be lighter I think...

I HIGHLY doubt this engine is pushing 200HP. It's a 2.0L 150 bored .30 over (supposedly) with velocity stacks and boyesen reeds.

I think any of that is irrelevant anyways, because a plain old 150 on this boat should rip out a skier in my opinion....

OK, so that kind of answers a.) It is normal for the engine to die when those exhaust ports get buried in the water....?
 
Boston enligtened you on one very important thing - the stator was replaced last year - if i were you that's where i would start - possibly the stator isn't functioning properly - is it a merc part? they have a one year warranty - have it tested. That boat should have no trouble pulling a skier up with that much motor.

As for the motor dieing, the releifs are probably to close to the water - they like to be about 6 inches up - omc had a huge problem with this in 87-88 with the 120-140's you'll see alot of those with drilled out reliefs.
 
Chris E said:
Boston enligtened you on one very important thing - the stator was replaced last year - if i were you that's where i would start - possibly the stator isn't functioning properly - is it a merc part? they have a one year warranty - have it tested. That boat should have no trouble pulling a skier up with that much motor.

As for the motor dieing, the releifs are probably to close to the water - they like to be about 6 inches up - omc had a huge problem with this in 87-88 with the 120-140's you'll see alot of those with drilled out reliefs.
Click to expand...

If the stator was not working, I would not see an increase in voltage when the motor was running versus not running, unless there is more to the stator than I am aware of. Also I would think that I would see problems all over the rev range if it was spark. However I will also check the stator's function to see if that could be the issue.
 
Does anyone else suspect fuel starvation? I have seen some posts regarding the old merc pulse pumps. I keep getting hung up on the fact that it runs fine after getting on plane....
 
Tell me what kind of RPM's are you turning at WOTwith both props. Let's take a look and that range and maybe we can get to the bottom of this as I don't think the. motor is the issue either.
 
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