Boat will not come up to speed

I have a 1997 175 Johnson ficht. I was out fishing when the power pack went out. I replaced it and it runs now. It will planeout and come up to speed sometimes, 60mph and 5600 rpm. Other times it will plane out and will not get over 44 mph and 4500 rpm. I can run for 3 or 4 minutes and it will surge a little and then come up to speed. Do any one know what might be wrong, any help would be appreciated. Thanks in advance.

Re: Boat will not come up to speed

Roy to get other than wild guesses you need to do some troubleshooting - - check spark plugs & spark - - have you tried squeezing the primer bulb when the rpm drops? - - - compression? - - sounds like you are dropping a cyl. I'll bet one of the plugs looks different.

Re: Boat will not come up to speed

Thanks solittle for the responce, I have checked compression, they range from 105-110, I have checked the bubble while running down the river when it start acting up and I have tried different coils because I have 3 extra. I did put different plugs in it and I cant tell any difference in them after a run on the water by pulling them out and looking at them. Would a plug break down and then work again? Thanks for the help.

Re: Boat will not come up to speed

Do you have any codes or lights/alarms? If the ignition module you replaced was used it could have a problem. Did you reinstall the metal RFI plate between coils and module? Since you changed the plugs are they the correct ones and are they indexed? Surging could be either a ignition or injector problem.....

Re: Boat will not come up to speed

Thanks fastbullet, Yes I did put the RFI plate back in and yes it was used, I am using the plugs that was recommended, qc12pepb. They are not indexed, The dealer told me torked was more important than index, I dont know. I do not have any alarms or lights. Thanks for the responce. What ever the problem is it seems to be working part time.

Re: Boat will not come up to speed

The plugs have to be indexed or the cylinder can miss fire or they can soot up. The gap cannot face away from the injector.

Re: Boat will not come up to speed

I will check them, Thanks faztbullet.

Re: Boat will not come up to speed

yes, i can also confirm that the plugs for sure have to be indexed on the fichts , your dealer told you rubbish. but on the other hand i do not think it will solve your problem . bad plugs or not indexed plugs will soot up quickly and give a bad starting, poor idling and stalling at trolling speed but should have very little effekt on the power when you go WOT. are the throttle cables correct, does all throttle bodies fully open every time ?

Re: Boat will not come up to speed

The motor starts fine and very easy, It has no mis at idling or on water hose, Some times it runs fine wot, some times it wont get over 4500 rpm. It was running fine until the power pack went out.I did check and the throttle body do open all the way. Thanks Aerobat.

Re: Boat will not come up to speed

hm... i think you have here an electronical, not a mechanical problem- especially when you write the problem starts after replacing the power pack.

it may be the little thing like a sensor which goes erratic for some time - one dumb question - did you not forgot to switch in again the air temperature after removing the air silencer?

its hard to say what, but like said- in think its a fault in the electronics.

nevertheless index the plugs or you will run in another problems soon.

Re: Boat will not come up to speed

I have double checked every thing I can think of including the air temp. sensor. I have ordered another set of new plugs, I will index these a see what happens. At least I can rule this problem out and they will be right. Thanks Aerobat for the help.

Re: Boat will not come up to speed

Ok, I put new plugs in and went to the lake, You all was right, It did not fix my problem but it does run better. First take off right up on plane and away it went.second take offf sputtering. I got back there squezeing bubble and had friend to drive boat and that worked. Every time I check my bubble it is soft. Do you think I got a bad bubble or a lift pump? Could the lift pump not be working completly and my resevoir running low?

Thanks Roy

Re: Boat will not come up to speed

yes, like said bad plugs will have little effect to top end -but now with the right indexed plugs you can exclude this for other problems. one more question : i assume you have the "originial" heads witout deflector pins or was an upgrade made

for now you say you have the soft ball- so it seems you have a fuel delivery issue. again- check the little things . prime the ball with engine off- does it get hard and stays hard for a time ? when yes i would not say its the ball- when not you may try to replace it. whatkind of tank you have ? is it properly ventilated ? what kind of fuel filter ( in the boat, not the engine)? clean and big enough? - remember your engine will have a fuel flow rate of easily 50 litres/hour when you drop the hammer- the filter must be able to handle it.

from my knowledge with a completely failed lift pump your engine would not run - but it maybe that the pump is weak and does not deliver enough fuel at WOT . but i am not sure if the engine should not throw a check engine light in this case.

at my evinrude ficht ram 150 i also had sputtering in the past , and sorted it out with new heavy duty filters and a water separator, and ich changed from XD30 to XD 50 oil. i was stunned that on this beast it truly makes a difference after some time. the engine runs smoother at trolling speeds and the prop hub with the exhaust is clean and not sooted up. i learned that with normal TCWIII oil the engine will run, but not good.

unfortunetly you will have to go step for step to sort it out.

Re: Boat will not come up to speed

'Bulb going soft' indicates to me that you either have a restriction or an air leak in the boat fuel system.
Bring along a separate fuel canister/tank. If the problem occurs, hook it in and see what happens.
Best is if you have it all pre-hooked and just switch a valve.

Re: Boat will not come up to speed

Ok, I finally figured it out after a few days of trial and era, I wont go thru the whole ordeal but i guess when my power pack went out and I was trying to find he problem I hooked up a gage on my fuel vapor line. I guess I got air in the vapor tank and it was traped. I bled it out and now every thing seems to be fine. Such a little thing cas cause so much trouble. I wont tothank every one on this forumfor there help and suggestions.

Thanks, Roy

Re: Boat will not come up to speed

Triton Roy said:

Ok, I finally figured it out after a few days of trial and era, I wont go thru the whole ordeal but i guess when my power pack went out and I was trying to find he problem I hooked up a gage on my fuel vapor line. I guess I got air in the vapor tank and it was traped. I bled it out and now every thing seems to be fine. Such a little thing cas cause so much trouble. I wont tothank every one on this forumfor there help and suggestions.

Thanks, Roy

Click to expand...

Ficht experts...is this for real? Air trapped in the vapor tank? Seems like the vapor tank will always have air in it...air and fuel vapor?

Re: Boat will not come up to speed

daselbee said:

Ficht experts...is this for real? Air trapped in the vapor tank? Seems like the vapor tank will always have air in it...air and fuel vapor?

Click to expand...

Probably not air in the vapor tank but air in the low pressure circuit between the tank and injectors. The tank itself is just like a carb float bowl with float and a needle valve to regulate from the feed pump and ventilated to let out air/vapor. The high pressure pump however may create 'bubbles' if running out of fuel or partly blocked screen filter.