Engine tune up?

Y

Yorkshirelad

Active Member
Oct 21, 2017
132
Stratford
Boat Info
340 Searay 86
454 Mercruisers with v drives
Ray-marine radar and gps
Engines
454 mercruisers
I headed out yesterday to a local anchorage and my old girl ran great (2 454,s 7.4 340 hp. But on the way back they ran fine cruising at 1500 rpm hull speed, but when I increased the rpms to get her on a plane 2800 to 3200 she started to miss like she was going to quit. I dropped back down to cruising speed and they ran fine again. On returning to the marina I booked her in for a tune, hope is a simple fix and not a valve or something, any ideas guys?
Cheers Rob
 
A tune could help but it sounds more like a failing fuel pump.
 
I purchased the boat last fall and had all the fluids changed out, but in the spring I didn’t have a tune up. The previous owner didn’t have records, so I changed out the stuffing box packing and the impellers. I’m going to speak with the service manager tomorrow.
 
I had same thing. It was a fuel pump. I replaced it with non OEM and it failed a few months later. I was in an area where I got another non OEM. It also failed. I replaced it with OEM been a couple of years it works fine. If it is on the port engine it is easy to change if it is starboard it is a bear. If on the engine there is a push rod that makes the fuel pump work. Pry it up and pack the area solid with wheel bearing grease to hold the push rod up.
 
Are you saying BOTH engines acted up at the same time? I assume your boat has 2 fuel tanks and each is running on it's own fuel tank. If that is the case it would be very odd that BOTH engines would act up at the same time. Since the boat is new to you and you have little insight I am suspecting bad fuel. Try hooking up a small 6 gallon fuel tank to the fuel pump to see if the problem goes away.
 
Hi Hottoddie,
I am suspecting the Starboard engine.
 
The problem solved!
Part of the electronic ignition is shorting out to the pole. The marina mechanic is going to service the boat on Monday.
 
Yorkshirelad said:
The problem solved!
Part of the electronic ignition is shorting out to the pole. The marina mechanic is going to service the boat on Monday.
Click to expand...

I hope you are correct but did the 'mechanic' diagnose the problem over the phone or was he physically at the boat?.....what 'pole' is he referring to and what part of the ignition system is shorting out?

cliff
 
I have electronic ignition, he started the engines and noticed the condenser on the ignition was sparking on the starboard engine, he said the new ones are insulated, he changes out about 10 a season. Wires are good I asked him to change out the plugs because most of my cruising is at hull speed.
 
Yorkshirelad said:
I have electronic ignition, he started the engines and noticed the condenser on the ignition was sparking on the starboard engine, he said the new ones are insulated, he changes out about 10 a season. Wires are good I asked him to change out the plugs because most of my cruising is at hull speed.
Click to expand...

great....I hope this solves the issue....

good luck...

cliff
 
Yorkshirelad said:
I have electronic ignition, he started the engines and noticed the condenser on the ignition was sparking on the starboard engine, he said the new ones are insulated, he changes out about 10 a season. Wires are good I asked him to change out the plugs because most of my cruising is at hull speed.
Click to expand...

Sounds like he is talking about the ignition sensor. The older style is open and tends to develop problems from corrosion etc, the new ones are sealed.
 
BillK2632 said:
Sounds like he is talking about the ignition sensor. The older style is open and tends to develop problems from corrosion etc, the new ones are sealed.
Click to expand...

don't think so....this is a 1986 boat.....probably has ignition points and condenser....

cliff
 
BillK2632 said:
Good point, he said electronic ignition but did also say condenser...
Click to expand...

I think some of the conversion kits to electronic ignition still used a condenser but could be wrong....that's been a longgggg time ago when I was messing with points....

cliff
 
Update! Problems fixed, tuned up both engines bad wires on the starboard engine, changed out both slave solenoids.
Has electronic ignition!
 
You must log in or register to reply here.

Forum statistics

Threads
113,119
Messages
1,426,564
Members
61,035
Latest member
Lukerney
Back
Top