1989 force 85 hp, 856x9h, boysen reeds. Irregular starting, irregular perforance.

[Austringer 101]

I have adjusted the throttle linkage, choke butterflies, accelerator butterflies. Will crank and not start, then start the next try. When underway, runs fine, then bogs down on acceleration after 3-4 attempts, takes off and runs fine until the next time. Float stuck? Varnish from old gas? This is on 1989 Spectrum 1700. Engine was rebuilt two yeas ago, properly broken in and no problems until now. I'm at 4500' elevation, jetted for this altitude. Turns 5000 + rpm

 

[jerryjerry05]

Water in the fuel?
​Choke not operating right?
Fuel pump diaphragm?

 

[Austringer 101]

Thank you for your reply. Siphoned the tank empty and refilled with fresh mixture, There is fuel under pressure at the carb lines. Adjusted choke to factory manual specs (which I bought as soon as I bought the boat and Clymer and Seloc) . I will check fuel pump diaphragm today, also pull the bowls off the carbs and look for trash. and pull the plugs. I'm running Champion 821 plugs instead of the surface gap plugs it came with.
What will the fuel recirculating system do if it's on the fritz?

 

[pnwboat]

I would strongly recommend that you replace the Champion 821 plugs with the surface gap type. Using the standard automotive style extended electrode can cause severe piston damage due to a hot spot. So hot that it can melt a hole right through the piston. I would do a compression check to see if the compression is good.

As far as the problem that you are experiencing, could be a fuel delivery issue or maybe ignition. It's a process of elimination. Go ahead and check the fuel pump and carb bowls like you mentioned. Also make sure the fuel vent on your gas tank is not plugged.

With the motor stopped and in the down position, squeeze the primer bulb 4 or 5 times. It should get firm. If it doesn't, then you may have a carb needle valve that is not sealing because it's either bad, debris caught between the needle valve and seat, or carb float level is not adjusted correctly. You could also have a bad primer bulb. If you don't already have one, you should have an in-line fuel filter between the fuel pump and carburetors for added protection.

The fuel re-circulation system burns off excess fuel that has built up in the by-pass passages and typically only affects low RPM performance.....around idle speed.

 

[Austringer 101]

Thank you. Pulled fuel pump, diaphragm OK, but will put in a new one while it's off. Pulled fuel intake tube, clean. Pulled hose off vent at tank blew through it, OK. Pulled all three carbs. Insides clean, no varnish, check floats, one a little off, jets clean. Will replace old stiff(but not cracked) fuel lines. Bulb seems to work.
Wouldn't Prestolite CD ignition either work or not work? Will put in surface gap plugs. Open to any ideas

 

[pnwboat]

Does your Prestolite system have the sky blue coils and CD Modules that are connected on a terminal strip with spade lug connections on the wires? Or does it have the black coils and CD modules that connect with tubular style plugs?

 

[Austringer 101]

Thank you for the reply. Blue coils and modules connecting to a terminal strip below with screw on connections

 

[pnwboat]

I guess it's a process of elimination as to whether it's a fuel delivery or ignition issue. Looks like you've covered most of the fuel delivery issues. One other thing to try. When it's bogging down, try squeezing the primer bulb at the same time to see if that has any effect. Also look at the primer bulb itself while under way. If you see the bulb start to collapse or suck in on it's own, then you have either a bad bulb or a fuel flow restriction between the bulb and the tank. Might be a bad fuel line or something blocking the fuel pick-up in the tank. You can try running on a separate portable tank and see if that makes any difference.

Do you have an inline see through fuel filter between the fuel pump and the carbs? If so, you can use it to trouble-shoot fuel delivery problems. It should always be pretty close to being full ( maybe 3/4 full minimum ) at all times and no bubbles while running. Bubbles mean it's sucking air. Low fuel level in filter and no bubbles, w/good diaphragm may indicate that one of the check valves in the fuel pump might be sticking.

As for ignition issues you might want to check the spade lug connectors on the wires going to the CD Modules and Ignition trigger. The factory often applies a small piece of black heat shrink tubing over the joint where the lug is crimped/soldered to the wire. It's not uncommon for the wire to break right at that joint. Since the heat shrink tubing covers that area, you don't see it, and the tubing holds the wire to the spade lug preventing it from completely separating and causing intermittent/poor connection.

Also make sure the ignition trigger wires that come out from under the Flywheel/Stator are intact and no insulation worn down to expose the bare wire. The trigger assy./wires move back and forth when you move the throttle back and forth.

 

[Frank Acampora]

Boyeson reeds do have a service life. Yours may be at their end. Try replacing them with stock reeds from a junk engine and see what happens.

 

[Austringer 101]

Thank you pnwboat. No in line filter as yet. Put new diaphragm in fuel pump and checked check valves, seem OK. Don't know any way to check wiring on terminal strip but to pull them of one terminal at a time and hook the ohm meter to the end and pierce the wire and move it to see what happens. Trigger wires intact.
Thank you Frank. The reeds went in in1991 and have appx. 484 hrs. on them. I still have the stock reeds, but when they were in it had a bad lag between idle and throttle up. That may be it because I haven't found anything that was really wrong so far. Drivin' me nuts. More later. Will contact Boyeson.

 

[pnwboat]

Last set of Boyesen reeds I ran had over 500 hours on them. I changed them just out of precaution. Frank's idea of tying the original style reeds, especially since you have them, to see what affect it has could be helpful.

 

[Austringer 101]

Talked to a tech at Boyeson. He said if there were bad reeds there would be oil leaking back on the inside of the reed holders (they are clean) and that at 480+ hours the reeds should be in good shape. He also said if the reeds were bad it would be continuous not intermittent. I'm going to leave them alone. Fuel lines from the QD on end of fuel line from tank to carbs all replaced. I'll keep looking.

 

[Austringer 101]

As of 3-12 I have put a new diaphragm in the fuel pump, replaced all the fuel lines from Just before the primer bulb to the fuel pump, fuel pump to carbs, between carbs, pulled the carbs apart checked jets and set floats, checked the reeds, pulled the control cable mechanism off and tightened loose bolts, replaces two missing nuts,lubed it put it back together, adjusted the cables at engine for shifter and accelerator, adjusted carb linkage, WOT throttle butterflies, checked choke setting. Also, since the overheat warning buzzer went off last time I had it in the water, I replaced the t-stat, t-state seal t-stat housing gasket, replaced the over heat sensor,put a new impeller in the water pump, drain, test and fill gear case. I still have not found anything I thought might have caused the problem with the possible exception of the old fuel lines might have had an air leak. I put the cuff on it, turned on the water, and it fired right up. Now to put it on the water and hope I accidently fixed it.

 

[Austringer 101]

I would like to thank everyone who responded and gave me things to think about. I put it on the water yesterday and excepting a couple minor glitches (idle too slow and the neutral start button lever needed adjustment) it took off and ran fine. No hesitation, no overheat warning. My only conclusion is that the old fuel line must have been letting air into the line. I was hard as a rock and the short pieces between carbs was squirting fuel when I pushed on it. This should be the end of this topic.