OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

I recently purchased a 1998 Four Winns Fling used from a second owner. All the information I can find from Four Winns, they never made a 98 but the registartion/title and all shows 1998 with the DOT.

Either way, I assume it has a 115hp OMC 2-stroke outboard turbojet engine. I have the manual to the boat but not the engine.

1. Does anyone know where to find a manual on this engine? I need to test the stator/power pack and most likely replace them.

2. What should the top speed be? When I am the only one in the boat, it gets on plane fast and speeds up to 35 quickly, sometimes I can hit 40 after moving on non-choppy water.

When my wife, 2 kids and I are in the boat I can only top out at about 25mph and it is tougher to get on plane. It is also difficult to turn right with all 4 of us in the boat, and when I do it slows down to about 20mph. Is this normal or do I need to start looking at something that could be bogging down the performance of the engine?

I mix 2-cycle oil 50:1 (16oz per 6 gallons) and recently put some additive to remove ethanol from the gas and also some carberator cleaner additive to the gas. I mix the oil because the alarm system on the oil injection mixing system was broke so it was easier to mix than to replace that unit.

It needs new plugs, I hear Champion gapped at .030 is correct. Does that sound correct?

When the engine is running in neutral or idle speed.. it "coughs" or "misses" once and again. To me this could be the plugs, but I am not sure.

It is kind of a bear to start. I turn the key over one slot, push the key in about 4-8 seconds to prime, put the throttle lever down to idle (with neutral button in) and turn the key... to ge it started I have to pump the throttle down to full speed a couple of times and then it goes. It may die a couple of times, but then starts back up and once it gets warm it runs fine. Seems failry normal for a 2-stroke but this boat has been a new learning experience despite my years of knowledge using/maintaining a 85 Procraft with 150HP Merc Black Max.

One of the blowers is MUCH louder than the other. I assume this means the blower itself needs to be tightened, does this sound correct?

Sorry for the amount of information and questions but I from reading this forum there are many knowledable people on this site but some of my questions have not been asked by others.

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Anyone?

Re: 1998 Four Winns Fling - Speed Question/Stator

Re: 1998 Four Winns Fling - Speed Question/Stator

Your post is too complicated and full of interesting, but useless, information.

Please simplify and keep it to one or two questions at a time.

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

JB said:

Your post is too complicated and full of interesting, but useless, information.

Please simplify and keep it to one or two questions at a time.

Click to expand...

My apologies, I will try and reduce it and provide some updates.

Not Resolved:
1. The boat goes 35-40mph with just me, when I add my wife and 2 kids (we are not big people) it tops out at about 25mph and has trouble turning right, slows down to 18-20mph and doesn't turn sharp. If turns fine when It is just me. Is this normal for this engine and boat?

2. Blower is really loud. I checked and it is mounted tightly to the boat. Do I need to just get a new one or is there something I can do to cut down the loud noise?

Resolved:
A. I found a manual
B. I figured out the correct Champion Plugs and Gap size
C. Starting troubles, it turns out that the starter was going bad and finally died on me this weekend, locked up. Found a brand new replacement, all is good!

Thanks in advance for any feedback and support.

Re: 1998 Four Winns Fling - Speed Question/Stator

Re: 1998 Four Winns Fling - Speed Question/Stator

Do you have a tach in her, feaster? What rpm are you getting at WOT, with and without your family??

I suspect an incorrect prop. What prop do you have on her?

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Thank you for your reply.

I do have a tach but it is not working, so it needs to be replaced. The prop is the factory prop and the part number matches up to the one listed in the OMC Turbojet Service Engine Manual. The prop is still in good shape also.

Yesterday I replaced the starter that froze up on me and it will not start, just cranks. So I check the plugs and they are wet with gas, the plugs are the exact match called out in the manual and gapped correctly, but I am not getting any spark from them. I cranked it once and heard a metal sounding pop under the flywheel and got a spark for about a second, then no spark afterwords. I am going to take the flywheel off tonight and see if the key pin is damaged, could be a timing issue but no clue yet!

Any ideas on what else could be keeping it from sparking? I get 12.5 volts at the battery, at the solenoid, 10.5 volts into the starter when it cranks and only 0.44 volts between the powerpack and plugs when cranking. The ground on the block is clean and tight, same with all the connections to the starter and solenoid.

It is dissapointing because it ran and then all of a sudden (without symptoms) it won't start.

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

It wasn't the flywheel key, not the safety switch.

Is there anyway to test the Stator, Power Pack and Coils? These are the only things I can think that would cause me not to get a spark.

Re: 1998 Four Winns Fling - Speed Question/Stator

Re: 1998 Four Winns Fling - Speed Question/Stator

If you have the OEM factory service manual all the test procedures are in it. The big thing is you'll need the proper test equipment.

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

I figured the proper test equipment was going to be the problem. I am replacing the power pack today, I noticed that the wires coming from the power pack to the coils were ran down the back of the block without insulation and they were melted. If that doesn't work I will move to the regulator/rectifier, then stator and then coils. After that I have pretty much replaced the entire igntion system other than the timer base assembly under the stator/flywheel.

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Today's Update - I replaced the power pack and coils... starts like a charm and run's like a charm!

New Problem: Once the engine started I throttled down a couple times, lot's of power! Seemed stronger than before it last ran, however there is water leaking out of the heads between the head gaskets and engine block. Only the left head, not the right. I immediately stop the engine and take it home. Checked the oil, no water in it. Checked all hoses and wires...all were in good condition and tight.

Plan: Remove both heads, take them to a machine shop and ensure they are level. Torque them back on (to specifications and sequence) with new gaskets and head bolts. Then pray, then do a compression test. If test is good, pray again, put it in the water and hope for the best.

Any feedback, experiences or comments are appreciated!

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Received the gaskets today. I will be installing them and then doing a compression check. With the engine running VERY good (even with a blown head gasket) and no water in the oil then my hopes are everything will be OK after this. Wish me luck!

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Today's Update - Starting to torque the bolts at 20 ft/lbs in sequence on the left head. Bolt #1, OK!, Bolt #2, OK!, Bolt #3, threads inside the block are stripped. Since it is only 20ft/lbs torque, I am going to drill the hole out, tap it and put in a helicoil and start over.

In order to prevent having to take the engine out, I am going to use a right angle drill. Let's hope it fits.

I will post updates after I get the heads on, hopefully.

Please provide any feedback or experiences you might have.

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Well, the helicoil worked, torqued to 20 ft/lbs on Bolt #3 and moved on from there! The only problem? Bolt #7 ended up doing the same thing! So, backed out everything again and will install another helicoil in the Bolt #7 position on the left head. Hopefully that is the last one that I will have to do!

Has anyone ever had this problem before?

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

I'd venture to say that it was a weekly, if not daily, problem for many of the salt water mechanics/magicians on this forum. You're not plowing new ground. Glad to read of your progress and determination.

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

AlTn said:

I'd venture to say that it was a weekly, if not daily, problem for many of the salt water mechanics/magicians on this forum. You're not plowing new ground. Glad to read of your progress and determination.

Click to expand...

Thank you, it is good to hear something like that. Keep's my determination going! Hopefully I won't have the same problems on any other head threads for either side of the engine!

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

If anyone has a working version of this motor they would like to sell, please let me know. Depending on how things go, that might be my next option.

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Re: 1998 Four Winns Fling - Ignition & Head Gaskets

Latest Update - Heads are tightened on successfully, compression test reads 120psi on the dot for each cylinder! Put it in the water, started great and ran great, even idled well! However, a good, but smaller, amount of water was now leaking from the water gaskets in the heads so I shut her down. The cylinder shalfts were dry, that is good! I figured this might happen so I had already ordered those gaskets, they come in tomorrow! Tomorrow I will put those on (let's hope no more stripped threads!!!!) and try her again.

I suspect my next obstacle will be that the gaskets in the exhaust manifold will need to be replaced, so I already ordered them. Hopefully those won't be hard to install and hopefully that will be the last thing I need to get her on the water again!

Any feedback or suggestions you might have would be appreciated!

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

I just bought a '96 with the same problem, hydro-locked. Head gasket was leaking water. You need to get the head and block machined so they are square. The engine had to have overheated at one point causing the warp. Also, if it's broken down, measure the bore and throw in some new rings. Don't keep replacing the gasket, it will re-blow every time and you'll run into more problems.

When I first looked at mine before buying, the engine was hydro-locked... wouldn't even turn over. Removed the plugs, turned it over and water come gushing out. Engine is easy to remove, 3 main bolts and about 5 hoses and 3 wire plugs... she lifts right out. A total rebuild for mine was $980... which included 4 hole bore, new pistons and all the machine work and gaskets. Dropping the motor in early next week.

What did you end up paying? I paid $500 because of it being locked... took a chance

Also, where did you find a manual? Is it a regular manual or mechanics?

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

When i replaced the water gaskets, i broke a total of 8 bolts on the heads, so be aware! Plus, one of the water cover was warped, as they are very thin. I had to order a new one.

Good luck!

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

I actually had a machine shop check the heads and block, they informed me they were not warped. A local certified evinrdue marine dealership checked the pistons and shafts when the heads were off and they said no need, they were fine.

Mine wasn't locked, it starts and runs great, has great compression just was leaking water.

Today I successfully put everything on and all is good! She started great, ran great, spitting water out the back like it should, engine stayed cool... all was good except a tiny leak under the left head. I discover that I didn't have the hose on good enough that goes into the head. Slipped it on further, tightened it up and the leak stopped! I even can get her up to 43mph now rather than 35mph and ran much faster with me, my wife and two kids than it did before it overheated.

I paid $2500 for this boat (NADA $3200) and have sunk about $700 extra into it including tools, manuals and parts and a new cranking battery. Parts were only about $300, tools were the majority of it. I have a nice collection now!

I got the service manual specific for this engine, I work for a logistics company and we do some business with BRP so I was able to order it directly from them.

I am just glad everything ended up OK and she is running better than ever. Tomorrow we are going to the lake, Sunny and 91 degrees!

Thanks for everyone who chimed in and provided help!