97 Rinker with 4.3 mercruiser

[Pmarshall]

I have a 97 Rinker Captiva with a 4.3 lx Gen+mercruiser. I’ve been having tons of issues. Bought the boat last year and it ran great. Marina winterized anddstored for the winter. The drain plug was left in over the winter and there was some water in there when I opened it this year. At first launch it wouldn’t start, fuel pump died on me. Changed it out and she started. Great! First trip out it was very hard to get on plane. When I did manage to plane it out, top end performance was low. I seemingly lost like 400 rpm and close to 10kmh. Changed plugs which happened to have bpr5es installed which are wrong since the nvm cross is 6efs, drained the gas and refilled. Now the idle is low. Idling around 400 and dies. But if I hit throttle only, it would run. Did a compression test(only the cylinder being tested at the time had plug removed. My mistake) all cylinindets read between 140-150psi. Now I try and start it and the starter spins but does Not engage. Also the anti siphon valve seemed fairly difficult to desert the ball via blowing but I confess I’m not sure how difficult it would be to de seat. What am I missing? I’m getting pretty frustrated here. Any suggestions on next steps? Did I burn my damn starter out now to? I’m hoping it just got too hot or somthing...edit: to start it I’ve had to prime it via pumps of throttle only this year. I don’t hear the hum of fuel pump for a few seconds when key is on, however I can remove the wires and jump the oil pressure switch, the pump runs. Could my oil pressure switch be bad???

 

[Rick Stephens]

Testing the oil pressure switch is pretty easy. Prime it by connecting hot to the outer lug on your starter solenoid. Get the carb full. Then fire up the motor, and as soon as idling, use a test light on both sides of the oil pressure switch. Both should be hot when you have oil pressure.

For test purposes, you can also screw both wires to one terminal, which bypasses the pressure switch entirely, runs the fuel pump as soon as the key is on. Don't run it on the wet that way other than an emergency measure to get back to dock if the pressure switch quits on a trip.

 

[harringtondav]

The oil pressure switch (not the gage switch) only closes when you've cranked long enough to build up oil pressure. It's a safety switch that stops the fuel pump (and engine) in a low oil pressure condition, and stops the fuel pump if the engine kills. I got tired of long cranking, so I jumped the switch wires permanently, and the pump starts at key 'on'. I watch my gages, so I'm OK w/the risk.

Since starter spins, the slave solenoid and 50A circuit breaker are OK. The start motor is also good. I suspect the solenoid mounted on the side of the starter isn't functioning correctly. It's closing the contacts to the B+ cable to the motor, causing it to spin, but not pulling the clutch lever to engage the pinion into the ring gear, or the clutch fork is broken or disconnected. I believe you have a PG 260 reduction drive starter motor. The solenoid assy is removed by removing two screws at the rear of the starter hsg. I haven't torn into mine, but if you are lucky you can disconnect the headed pin from the slot in the clutch arm and see what is going on. You can bench test the solenoid by connecting B+ to the large battery terminal, and B- to the 'S' terminal. The solenoid plunger should pull in. Since the motor contacts close, I suspect the clutch linkage is loose or broken. See this link for a parts breakdown. I'd go w/Sierra aftermarket parts, they've never failed me, and are often from Merc's.supplier. iBoats prices are often the best, but shop around. http://www.marineengine.com/parts/m...hru-0k999999/starter-motor-pg260-and-pg260-f1

 

[Pmarshall]

THanks. I did bypass the oil pressure sensor by jumping the 2 wires together. The starter was cranking fine during my compression tests but at the last cylinder it made an awful sound and I stopped. After I put the wires back on and tried to start again, it would just spin. I didn’t check the battery gauge but since it was spinning I’m going to say that was fine. What about my low idle issue? I am getting fuel to the carb, I have not tested spark yet. It runs at about 1200 rpm but as soon as I put it in neutral it sputters and dies out

 

[porscheguy]

Check/change fuel water separator.

 

[Pmarshall]

Changed separator yesterday

 

[Rick Stephens]

I got tired of long cranking, so I jumped the switch wires permanently, and the pump starts at key 'on'. I watch my gages, so I'm OK w/the risk.

So..... the issue with that is the tiniest piece of dirt or just a gas crystal that gets into your float needle and you are pouring gas into the carb and motor. So it floods your motor and it dies. And as long as the key is on, you are pumping fuel. So your first next step is try to restart, all the while cranking out fuel. That is one of the scariest safety breaks I can imagine. I strongly recommend you fix the back flow problem that is draining your carb back into the tank so you don't have starting issues. I added a check valve between separator and pump.

 

[harringtondav]

Rick Stephens . I'm listening, and considering. I've wondered about some back flow/drain on my Weber 4 bbl. Do you have a link for this check valve? I've got flaring tools to splice it in, but I recall there isn't a lot of space in that vertical SS fuel tube below the pump. So I'll still consider the risk. I listen to the elec. fuel pump, and don't crank until I hear it stall, as it always does once the float needles are up tight in their seats.

Blocked open needle valves can flood mechanical fuel pump 350 Mags, and 350 Cruisers, and any of the old carb cars I've owned. Once flooded, you chill for a while, WOT slowly to not accel. pump too much more gas and touch it off. Explosions are very rare. Gas in the crankcase oil is more common, but it eventually evaporates.

 

[Rick Stephens]

Difference with a mechanical is it doesn't pump unless the motor is turning. An electric pump connected to ignition will pump all the time the key is on. Even cars and trucks only run electric pump for a few seconds when you turn your key on until after the motor starts. Might ask AllDodge to share some thoughts.

 

[Pmarshall]

Starter now engaged intermittently. Going to pull it this evening. Any suggestions on my poor/no idle??

 

[Rick Stephens]

Starter now engaged intermittently. Going to pull it this evening. Any suggestions on my poor/no idle??

Quite the list of things to work on.

First thing, 1200 RPM at idle is too high. Engaging gears will be tough on the dogs, rounding corners off. Potentially breaking stuff. Specification is 650-700 RPMs at idle. Getting it to run there may mean doing maintenance to the motor. All else being mechanically sound, you need to look at ignition (cap, rotor, wires, plug, timing) and carburetion (clean fuel, fuel lines and anti syphon valve, filters, pump, and of course the carburetor).

Once the engine is running correctly, and idling within spec, then you can address what happens when you shift into gear. Most common source of the engine dying is a worn or sticky lower shift cable. When you try and move the shifter into or out of gear, a sticky worn lower shift cable will activate the shift interrupt switch and kill your motor. First step in the process of fixing this is to learn how the shift interrupt works so you know why it is failing on you. Read up in the Adults Only Section at the top of the Mercruiser Repair Forum and it will tell you all about the Shift Interrupt. This is essential knowledge if you are going to work on your Mercruiser yourself.

 

[alldodge]

post 1 - Now the idle is low. Idling around 400 and dies. But if I hit throttle only, it would run.

post 4 - tried to start again, it would just spin.
What about my low idle issue? I am getting fuel to the carb, I have not tested spark yet.
It runs at about 1200 rpm but as soon as I put it in neutral it sputters and dies out

Might have it wrong but here is my take. The motor only idles around 400 rpm and when the throttle is moved to idle position the motor dies. The motor can be kept running by using throttle only and keeping it up around 1200.

Don't need to check for spark because it does run

I think you need the carb rebuilt or replaced your idle circuits are clogged and there is prbably an issue with the main jets and would be the reason for a loss of rpm at WOT